As Mayor, I have seen us through a triumphant Jubilee and the terrors of the Black Hood killer. But my friends, it has taken a personal toll. I have decided to step down as Mayor, to spend more time with my family and to return to my own legal career right here in Riverdale.
McCoy is not only the powerful and fabulous Mayor of Riverdale, but also the mother of soon-to-be-world-famous Josie, of Josie & The Pussycats fame. Chic and driven, Mayor McCoy is struggling to guide Riverdale through the crisis precipitated by the mysterious death of Jason Blossom, all while making sure the town’s upcoming 75th Jubilee Celebration goes off without a hitch.
Sierra McCoy grew up in the small and close minded town of Riverdale. She attended Riverdale High School, and later proceeded to raise a family with Myles McCoy. The two of them have a daughter together, named Josie. Some time after this, Sierra became Mayor of Riverdale, and while some people are opening up, everyone in town was not so welcoming of a mayor of color.
Before the Pep Rally kicked off, Mayor McCoy joined Mr. Weatherbee and Coach Clayton on stage to thank everyone in attendance. She was gladdened by the turn out. A lack of heart and school spirit had never been the Riverdale way, even in spite of the weather and mysterious death of Jason Blossom. She reminded the crowd that the pep-rally is like no other they've had before, which is why she dedicated the evening to the memory of Jason Blossom. She then welcomed the River Vixens and Josie and the Pussycats to the stage to perform. 
Taste of Riverdale
Mayor McCoy welcomed everyone to the first annual Taste of Riverdale. She went on the say that the event taking place, proved that Riverdale is a town that when tragedy strikes, they pick themselves back up. After her speech, Sierra approached Cliff and Penelope Blossom, just to check in on how they're dealing with Jason's death, but she found herself on the end of a snarky reply from Penelope instead. 
Mayor McCoy apologized to Jughead as there was nothing she could do in stopping the demolition of the Twilight Drive-In. Good riddance, it's a cesspool filled with criminals. With Andrews Construction sanctioned to demolish the lot on Monday, the deal is done. When Jughead was younger, his family would always go to the drive-in, he and his sister, Jeallybean, would hide in the trunk as they couldn't always afford tickets, the drive-in is like his home. While, she appreciated the sentiment that he holds towards the drive-in, the future of Riverdale is at stake.
Mayor McCoy later received a secret donation from Hermione Lodge towards her re-election campaign, in exchange, Lodge Industries would receive the twilight drive-in, which is one of the most prime pieces of real-estate in Riverdale. She made a point to remind Hermione that no one could know of their deal, especially not the Blossoms. 
Annual Variety Show
Upon learning that Valerie had quit the Pussycats, Sierra believed the best solution was to replace her, as everyone is replaceable with the exception of Josie. With Myles McCoy, Josie's father attending their performance at the Variety Show, she would hate for Josie to let him down, especially since he had to cancel two concerts. She insisted that Josie find a new member, someone skinny, beautiful, and of color.
She was then invited over for dinner by Fred Andrews and Hermione Lodge, in an attempt for them to plead his case for the construction contract of the land that once housed the Twilight Drive-In. The topic of discussion changed several times throughout the night before ending with Fred's bid, one that Sierra was more than willing to grant him, as she described Fred as a working man who lived in the real world and found his bid refreshing. However, the buyer was already in the process of accepting another bid and it would take two share-holder signatures to stop the process and the chances of that happening were fairly unlikely.
The night of the Variety Show had finally come, Sierra and Myles sat in the audience as Josie and the Pussycats performed on stage, Sierra thoroughly enjoyed her daughter's performance, Myles, on the other hand, was left unimpressed, as he exited the event halfway through the performance. After the show, she found Josie in tears, so Sierra hugged her tight. 
The murder of Jason Blossom had revealed several dark truths, none of which Mayor McCoy was eager to face, as she screamed at Sheriff Keller to destroy every last trace of corruption.
In the days leading up to the 75th Anniversary Jubilee, Mayor McCoy approached Archie Andrews and Betty Cooper with an offer to feature them both at the event, in their honor since the two of them helped bring peace and justice back to the streets of Riverdale. She informed Archie that the Pussycats would be performing at the Jubilee, so she would love it if he could join them. As for Betty, Mayor McCoy simply wanted her to speak at the event, she thought it best if the townspeople of Riverdale heard from their best and brightest. Archie inquired about Jughead, who also played a large role in solving the mystery of Jason death. While she was fond of him, and he was more than welcome to attend the Jubilee, the Mayor thought it would be confusing to have him up on stage while his father was locked up at the same time for his involvement in Jason's death. She reminded Archie and Betty that they were the heroes that the town desperately needed.
The night of the Jubilee had finally arrived, as Mayor McCoy welcomed all to the Town Hall in celebration of the town's 75th anniversary. She couldn't have been any more thrilled to introduce her daughter, Josie, and her Pussycats, alongside Archie. Much to her surprise, Josie and Archie would not be playing the song she had previously signed off on, instead, they played one of his sings. Initially upset and confused, she came around to enjoy the song as the crowd applauded their performance. Unfortunately, the Jubilee went a bit off the rails as Betty gave her speech in front of the entire town, accusing them all of writing off FP Jones because everyone was so quick to place the blame on him. Betty went on to explain that the town was at a crossroads, and that each of them needed to do better or else what happened to Jason wouldn't be the last. From backstage, Mayor McCoy didn't look too pleased. In fact, she looked discouraged, perhaps at her own behavior.
Mayor McCoy arrived at the office to find Betty and Jughead awaiting her arrival. With the Chock'lit Shoppe on the verge of closing, the two of them sought to let Pop Tate know that the entire town was rallying behind him. They were hoping that the Mayor could make the diner a landmark or declare a day for Pop Tate in support. Unfortunately, Mayor McCoy couldn't take the risk. What if she endorsed Pop's, and next week someone else is shot, she asked. Her priorities as a Mayor and a mother was to keep the town safe by any means necessary, so if that meant the closing off Pop's shoppe, then so be it. Jughead then ambushed her with questions regarding his father's case, in which he was being shipped off to a state prison for a murder he didn't commit. FP made his own poor choices, and now it was time to deal with them. With that being said, Jughead instructed the Mayor to remember this very moment, as it is the moment that she turned her back on both Pop Tate and FP.
Another Killer on the Loose
Mayor McCoy met with Sheriff Keller and the Coopers after learning that they received a letter from the supposed killer. In this letter, he confessed to the murder of Geraldine Grundy, as well as the shootings of Fred Andrews, Moose Mason, and Midge Klump. He even provided proof of these heinous crimes, ridding all doubt on whether or not he was, in fact, the killer they were searching for. With the letter, was Fred's missing wallet and Geraldine's glasses. In the spirit of public safety, Mayor McCoy asked that Alice not print the Black Hood's letter. However, Alice wasn't too keen on withholding the letter from the public. So, before turning the letter over to Sheriff Keller, she had made a copy of it and sent it in to print for tomorrow's front page. 
With a killer amongst them, leaving the residents of Riverdale in fear, Mayor McCoy scheduled a Town Hall meeting for Wednesday at 7:00 PM.
Mayor McCoy welcomed the parents of Riverdale as the Town Hall meeting commenced. She shared their concerns over the safety of their town and their children. The purpose of the scheduled meeting was to answer their questions, and if she could, to ease their minds. Sheriff Keller then took to the podium to announce that due to their tight budget, they would be putting together a helpline that people could call in order to report any suspicious activity. Sounds an awful lot like the Red Circle's hotline to me, Alice interjected. In response, Mayor McCoy joined Sheriff Keller at the podium to ask if Alice had an actual question, which she did. Alice was wondering when they were going to address the real problem in Riverdale, that being the southside. All in due time, Mayor McCoy replied. But they were there to talk about the Black Hood, not the Southside Serpents or the drugs being trafficked through that side of town. She announced that the Sheriff had a plan he was putting in place, beginning with a town-wide curfew. Alice suggested that as a show of strength, they shut down Southside High, and use that money to hire more deputies, who could then protect their children.
As Alice continued to demonize the southside, Fred Andrews came to their defense, explaining that they needed to unite as a town. Only then would they stand a chance of surviving. It was then that Betty and Jughead entered Town Hall to warn everyone about the Black Hood's supposed arrival. After the lights shut off, Mayor McCoy urged everyone in attendance to stay calm and remain in their seats, though they quickly evacuated after Betty pulled the fire alarm.
Following the Town Hall meeting, Mayor McCoy and Sheriff Keller stopped by the Cooper house in an attempt to better understand how Betty and Jughead knew where the killer would strike next. Betty handed them a letter,
which was sent to her by the Black Hood, along with the cipher that she had earlier turned over.
Declaring War on the Southside
Sierra and Josie arrived at Alice's home after she discovered that Josie and several of her friends attended a party at the Five Seasons, where Jingle Jangle was in use. Sierra thanked Alice for hosting the gathering as she agreed with Alice's sentiment of coming together, so that they could deal with the children's inappropriate actions appropriately. The get-together proved to be quite informative, having learned that Reggie Mantle supplied the drugs at the party, and that his supplier was a kid at Southside High, who he believed to be a member of the Southside Serpents. Sierra then learned that not only did Josie attend the drug-fueled party, but that she participated in the night's events, despite knowing that her father struggled with addiction. Before leaving with Josie, as the Mayor, Sierra announced that moving forward, her number one priority was bringing the Southside under control, even if that meant razing it to the ground or arresting every Serpent in sight.
After the gathering, she and Sheriff Keller raided Southside High, kicking in its doors, searching lockers, and arresting young Serpents on sight, specifically Toni Topaz and Sweet Pea.
An Affair with the Sheriff
Mayor McCoy and Sheriff Keller were called down to Pop's Chock'lit Shoppe after Pop Tate discovered a letter from the Black Hood affixed to the diner's door. In this letter, the Black Hood issued a test, one that would last all of 48 hours. He asked the people of Riverdale show prove to him that they were pure of heart. However, should they fail the test, and continue to sin, the attacks would resume.
That night, Sierra awaited Josie's return at the Five Seasons, which she moved herself and her daughter into because she didn't feel same at their house. Sierra confronted Josie as she entered the hotel room. She didn't want her walking the streets alone, especially with the Black Hood on the loose. She was growing so concerned that she had even considered assigning Josie a deputy, for security. Josie insisted that she didn't need a bodyguard. Seeking to secure her daughter's safety, Sierra told Josie that from that moment forward, she was to be in the hotel room, before dark.
The following night, with Sheriff Keller in tow, Sierra went out looking for Josie, who failed to make it home before dark. She and the Sheriff found Josie dancing in Pop's shoppe with Chuck Clayton, who the Mayor wasn't pleased to see around her daughter. "You're a damn fool", she stated. She had sent Josie several texts messages over the hours, all of which went unanswered. Chuck then interjected, explaining that he was just about to give Josie a ride home. However, Sierra didn't even want him within 10 feet of Josie.
Back at the Five Seasons, Sierra tried to make sense of Josie's recent behavior, concluding that she was merely acting out, which Sierra couldn't stand for, not with the Black Hood terrorizing the streets. Josie's dismissed the notion that she was acting out, claiming that she was simply living her life. Sierra reminded Josie of all the people in Riverdale with hate in their heart. The same people that used to write her awful letters. Since the Black Hood emerged, the letters had gotten worse. It was almost as if they were emboldened by the killer. Sierra informed Josie of the recent death threats. The things that were being said were terrifying, such as threatening to slit her throat or cut out her heart. Some of the residents of Riverdale were monsters. To make matters worse, the last letter she got, mentioned her daughter. Sheriff Keller then asked if Josie had received any suspicious letters or packages recently, which Josie replied that she hadn't. Sierra had worked so hard to get them where they were at, to shield them from such hate. She then joined Josie on the couch, and held her close.
Sierra comforted Josie the following night after learning that she had received a pig's heart as a gift, while at school. They suspected Chuck of being the culprit. Sheriff Keller had talked to him, and he promised he'd be leaving Josie alone. However, the Sheriff wasn't convinced that Chuck was responsible. After questioning him and checking his locker, they never found any evidence. Sierra instructed Tom to keep looking because if Josie said that it was Chuck, then it was him.
In the late hours of the night, Sierra ran into Josie's room as she had woken up in a panic, gasping for air and holding her throat.
Later that night, at the Shady Palm Motel, Sierra heard a knock at the door. On the other side was Tom, who she greeted with a kiss before inviting in.
With Christmas and the Black Hood behind them, Riverdale began to regain a sense of normalcy, starting with Mayor McCoy, who began conducting secret business meetings with Hiram and Hermione Lodge, one of which took place in Hiram's study at the Pembrooke.
The following day, at the Mayor's office, after getting off the phone with Principal Weatherbee, Sierra discussed the abrupt closing of Southside High with Hiram and Hermione. She predicted that at any moment, her phone would start exploding with calls from outraged parents about the news of Southside students being relocated to several other Northside schools within the district. Hermione attempted to ease Sierra's concerns by telling her that it would only be news for a couple of days before blowing over, using the Black Hood and how quickly the town has forgotten about him as a reference. After a few weeks have passed, Hiram explained that they would quietly go about purchasing the land beneath Southside High. In return for her assistance, Hermione assured Sierra that she would receive a sizable donation towards her re-election campaign. Just then, Sierra's phone began to light up with phone calls.
Sierra attended a meeting at the Andrews house alongside Sheriff Keller, Fred Andrews and the Lodges where they discussed the Southside students who had transferred to Riverdale High. While the students were fine, Sierra was dealing with their outraged parents who were in her office everyday to demand that she reopen Southside High. Luckily, Hiram, Hermione and Fred had discussed how their new neighborhood could use something positive to focus on. With her blessing, they wanted to make Pickens Day a celebratory event. Sponsored by Lodge Industries with Andrews Construction co-sponsoring. Sierra took from this that they wanted to make Pickens Day a commercial event for their SoDale project, similar to their open house. "Au contraire, madam Mayor", Veronica responded. The open house was for investors while Pickens Day would be for North and Southsiders alike. Two halves of a whole coming together. Sierra worried that trying to distract people with a party would backfire, resulting in violence. Not to mention that the Southside Serpents were still a reason for concern. Even though they had been laying low, they were still wild cards. Having prepared for just that scenario, Hiram, Hermione and Fred had offered to hire the Serpents as security for the event. Sierra asked if Fred was on board with Hiram and Hermione's plan. Fred backed the them up, reasoning that since FP had told him that the Serpents were looking for work, it made sense to allow them to keep the peace. The party was an opportunity to let the Southside know that they hadn't been abandoned. The meeting, unfortunately, came to an abrupt end as Archie returned home.
Sierra returned home to the Five Seasons hotel the following day to find that Josie and Veronica were in search of musicians were and that they were bringing back the Pussycats to play at Pickens Day. Whose idea was that, Sierra asked, to which Veronica claimed responsibility. Sierra was displeased to hear about their plans to reunite the Pussycats given that Josie was supposed to be focusing on her solo career. Hoping to avoid any further conflict, Veronica suggested that they bill it as a special event, one-night only. However, Sierra rudely replied that she was talking to Josie. In fact, she'd rather they continue the conversation at a later time, once Veronica was gone.
A couple days later, Sierra angrily approached Josie with Jughead's published article from the Blue and Gold which accused General Pickens of slaughtering the Uktena tribe for their land many years before. While she couldn't cancel Pickens day, she could surely keep Josie from performing at it given that the town was extremely riled up in the wake of this article. She feared the possibility of a riot. Josie assured Sierra that no one was rioting, furthermore, she had promised Veronica that she would perform. Sierra replied that Josie can tell Veronica that the Pussycats aren't hers to order around. Hearing the anger in her voice, Josie wondered why the mere mention of Veronica was triggering Sierra all of the sudden. In an effort convince Josie out of performing at Pickens Day, Sierra told her about the Lodge's way of doing business. And the way they used Veronica to do their business.
Sierra and Josie arrived in Pickens Park on Pickens Day for the celebration. Upon their arrival, they were greeted by Hermione. She was glad to see that they made it but disappointed to hear that Josie wouldn't be performing alongside Veronica. Sierra explained that she had forbade Josie from performing following the publishing of Jughead's article because of the possible dangers she could face. A little while later, an upset Sierra and Josie watched from the crowd as Veronica took to the stage to perform with Valerie and Melody with what was being called "Veronica and the Pussycats". Half way through their performance, the Serpents marched into the park with duct-tape covering their mouths and signs that read 'honor this land' and 'sacred land'. With Sweet Pea and Fogarty at her side, Toni, who seemingly led the protest, stood in front of the stage to announce that they represented the dead and the silenced. Pickens Day was a lie. General Pickens slaughtered the Uktena tribe, Toni's grandfather's family. And the land in which they were standing on, would soon give way to a new Southside, which was stolen from them. While the Serpents couldn't bring them back, they could at the very least honor them. Looking prevent a riot, Hiram got on stage to applaud the Serpents for standing up for justice, as well as the honor and legacy of the Uktena, who contribute to the rich tapestry that is Riverdale, that is the Southside and that will be SoDale.
The following morning, Sierra and the Lodges were assembled in Pickens Park by Sheriff Keller, who alerted them of the desecration of the General Pickens' statue. Its head had been removed and red paint covered the statue to simulate blood. Since Hiram and Hermione were calling the shots, Sierra asked how they would like it to be handled. Hiram demanded that the investigation of the missing head be handled swiftly and with extreme prejudice given that the most likely suspects were the Serpents.
With Pickens Day behind them, Sierra and Josie stopped by the Pembrooke to offer an apology. She had misgivings about some of the decisions Veronica's parents were making which was admittedly wrong and inappropriate. Given the stressful times, neither Veronica nor Hermione held any grudges. As proof of that, Veronica invited them both to her confirmation ceremony. Sierra graciously accepted their invitation. It made giving them their gift that much easier. By gift, Sierra was referring to Josie's offer to sing at Veronica's confirmation. While Veronica already had plans to sing herself, Hermione accepted Josie's offer for her so that they could perform together. When Veronica asked if Josie knew the "Bitter Sweet Symphony" from the Cruel Intentions soundtrack, Josie replied that she could learn.
Later that day, Sierra received a surprise visit from Jughead who came to confront her on the witch-hunt for the Southside Serpents. They had nothing to do with the beheading of General Pickens' statue. Jughead surmised that she knew that. But in the mean time, she's still tightening the screws and sending Sheriff Keller to sow seeds of unrest by threatening to take their homes away. Since when did she care about the statue of a murderer, Jughead asked. Sierra answered that Governor Dooley called and read her the riot act. That statue cost him a lot of money and he was furious. Regardless, Mayor McCoy was supposed to be an ally. So Jughead questioned why she was doing what she was doing. It was then that he realized that someone was pulling Sierra's strings. He suspected that Hiram Lodge was the puppet master. Admittedly, she liked Jughead as he was a bright kid. So Sierra warned him to back down before she uncovered something that he shouldn't.
Later that week, the day of Veronica's ceremony had finally arrived. Sierra sat with the other guests as Veronica and Josie sang Bitter Sweet Symphony. After Veronica was anointed and confirmed, the guests headed over to the Pembrooke for the post-confirmation party. It was there that Sierra congratulated Hiram and Hermione on a beautiful service. With the sales finalized, she informed them that they were now the proud owners of what was previously Southside High.
Resigning as Mayor
Sierra was paid a surprise visit from Jughead at her office, who with a map of the Southside, asked what Sunnyside Trailer Park, Twilight Drive-In and Southside High all had in common. He told her that they were or are town land. The drive-in was shut down, as was Southside High. Now the trailer park was in jeopardy. Jughead could feel the invisible hand of Hiram Lodge all over it. Sierra stood from her seat and asked Jughead what it was that he was insinuating. If she was accepting donations from the Lodges in exchange for favors such as land deals, then Jughead advised her to take this chance to come clean to the public.
The following night, Sierra got into an argument at the Pembrooke with Hiram and Hermione on how they would proceed with their plans for the Southside. Sierra exited the study in a fit of rage, and on the way out, she told them that she was fairly close to telling Jughead everything and that it would be a lot worse for them than it would be for her. The argument in question was due to the expose that Jughead was writing about them. Given that they didn't have much time, Hiram and Hermione decided it was best to accelerate the timetable. So they told Sierra they might have to announce their plans for Southside High earlier than expected, but she refused and demanded that they wait until after she's reelected. Should they proceed without her, she threatened to expose them
Later that night, Sierra was warned by Veronica about her parents' plan to expose her. Veronica knew that whatever questionable arrangement the Mayor had with her parents was imploding, and that she was trying to go after them in some way. But Veronica revealed that they were planning to discredit her, to get her out of the office and neutralize her by exposing her affair with Tom Keller. Veronica told Sierra that she could still get out of it by taking control of the narrative and inoculating herself.
Taking Veronica's advice and warning to heart, the very next day, on live broadcast, with Josie at her side, Sierra resigned from office. As Mayor, she had seen them through a triumphant Jubilee and the terrors of the Black Hood killer. But it had taken a personal toll, so she claimed. She had decided to step down as Mayor, to spend more time with her family and to return to her own legal career right in Riverdale.
While Sierra and Tom supposedly discussed installing a security system at the law firm, Josie returned home, to the Five Seasons, interrupting their discussion. As Tom exited the room, Sierra explained to Josie that she cared for him. While Josie understood, it was still weird to see them together, especially when her father still didn't know. Unbeknownst to Josie, Myles did know about the affair as Sierra had told him. They were initially going to wait until after Josie's graduation but Sierra decided it was time to reveal to Josie that they were getting a divorce. Josie asked if Tom was going to get a divorce as well. Sierra told her that he had to talk to his wife, who was overseas and Kevin first. Sierra insisted that they respect that.
Later that night, Sierra confronted Josie after learning from Tom that Josie had told Kevin about the affair. She credited Josie for a lot of things, but never for being cruel. Because of Josie's interference, Kevin was no longer talking to Tom, who was also still trying to reach his wife overseas. However, Josie believed that she did the right thing in telling Kevin, hoping that it would provide him with the chance to save his parents' marriage since she couldn't save hers. Their lives were imploding, which Josie blamed Sierra for. However, according to Sierra, that was the Lodge's doing as this wasn't how she wished for the affair to come out, but that choice was taken away from her, just like Josie took that choice away from Tom and Kevin, even if it was unintentional.
Later that night, per Josie and Kevin's request, Sierra and Tom met at Pop's Chock'lit Shoppe with their children. They were assured that it wasn't a trap, but when Kevin and Josie were talking after the movie at the Bijou, they realized that the conversation was bigger than all of them and that it was probably going to be a long one. So they believed it was best if they started talking about it.
The next day, Sierra went to go see Fred Andrews as Josie and Archie were hoping that she could convince him not to run for Mayor, thus furthering his involvement with the Lodges. She told him of the less glamorous side of being a mayor, like the townsfolk turning on him and filling potholes. Not to mention the uglier aspects of the job such as crime, poverty and threats.
The next day, outside Town Hall, Sierra and Josie watched as the Lodges held a press conference to announce that Hermione Lodge would be running for Mayor.
Sierra is a beautiful middle-aged woman with a slim figure. She has dark skin, brown hair, and deep brown eyes. She often wears a lot of makeup; lipstick, eyeshadow, etc. As for her clothing choices, Sierra typically has on long, dark-colored dresses.
Sierra is a proud and confident woman of color, often encouraging her daughter, Josie, to embrace the same qualities within herself. Having been elected as Mayor in such a small-minded and secluded town, Sierra was subject to hate, which presumably took a lot of heart and bravery to withstand. More than just a Mayor, Sierra is also a caring mother, being there for Josie in her time of hurt and motivating her to achieve her dream of becoming a famous singer.
The relationship between Josie and Sierra McCoy is tight and close-knit. They care deeply for each other, as a mother and daughter would. Even though Sierra may be strict toward her daughter, it is only for her daughter's benefit. She pushes her to achieve her goals and is proud of her for her accomplishments such as the band, Josie and the Pussycats, unlike her husband Myles McCoy, who only sees it as child's play.
At some point, Myles and Sierra met and later went on to marry and have a daughter together, Josie. Due to Myles's career as a professional jazz player, he is often absent, causing the relationship between him and Sierra being quite distant with each other. It also appears that they often have disagreements with each other, as Myles is quite strict on their daughter Josie when it comes to her band, Josie and the Pussycats, looking at it as nothing more than child's play, whereas Sierra is more calm with Josie, and proud of what she's accomplished, pushing Josie to achieve her goals.
Initially, the relationship between Tom and Sierra appeared to be strictly business. With him being the town's Sheriff and Sierra being the Mayor, it was perfectly normal to see the two together, however, due to them spending a lot of time with each other, at an unknown point, they two started to develop romantic feeling for one another, and began having an affair. It is unknown as to how long they've been together, but with Sierra's distant relationship with her husband, Myles McCoy, and Sheriff Keller's absentee wife, it is possible the two were able to find common traits with each other, thus leading to their current relationship.