- "It is heartening to see so many of you here, even in weather like this. But a lack of heart and school spirit has never been the Riverdale way. Tonight's pep rally isn't like any other we've had in the past. And we shouldn't pretend that it is. Which is why I would like to dedicate this evening to the memory of one of our brightest. Jason Blossom. We're with him tonight. "
- —Mayor McCoy to the crowd[src]
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.
Before the Pep Rally kicked off, Mayor McCoy joined Mr. Weatherbee and Coach Clayton on stage to personally thank everyone in attendance. She is gladden by the turn out, a lack of heart and school spirit has never been the way of Riverdale High School, 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 Jason Blossom. She then welcomed the River Vixens and Josie and the Pussycats to the stage to perform. 
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. 
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 diner 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, then finally ending with Fred's plead, one that Sierra was more than willing to adhere to, she described Fred as a working man, who lives in the real world.
she found his bid to be refreshing, if it wasn't for the buyer already being in the process of accepting another bid, then she'd give him the contract, but it would take two share-holder signatures to stop the process, alas, the chances of that happen 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. 
Sierra is a beautiful middle-age woman with a slim figure. She has dark skin, brown hair and deep brown eyes. She often wears a lot of make up; lipstick, eye shadow, etc. As for her clothing choices, Sierra typically has on long, dark colored dresses.
- "Chapter Two: A Touch of Evil"
- "Chapter Three: Body Double"
- "Chapter Four: The Last Picture Show"
- "Chapter Six: Faster, Pussycats! Kill! Kill!"
- See also: Category:Images of Sierra McCoy
- ↑ ‘Riverdale’: Robin Givens Cast As Riverdale’s Mayor In The CW Series - Deadline
- ↑ Aguirre-Sacasa, Roberto (writer) & Krieger, Lee Toland (director) (February 2, 2017). "Chapter Two: A Touch of Evil". Riverdale. Season 1. Episode 2. The CW.
- ↑ Lawrence, Yolonda E. (writer) & Krieger, Lee Toland (director) (February 9, 2017). "Chapter Three: Body Double". Riverdale. Season 1. Episode 3. The CW.
- ↑ Grassi, Michael (writer) & Piznarski, Mark (director) (February 16, 2017). "Chapter Four: The Last Picture Show". Riverdale. Season 1. Episode 4. The CW.
- ↑ Williams, Tessa Leigh & Zwart, Nicholas (writers) & Adelson, Steve (director) (March 2, 2017). "Chapter Six: Faster, Pussycats! Kill! Kill!". Riverdale. Season 1. Episode 6. The CW.