|“||Even though we were twins, I used to demand I have my own birthday party. Until one year, out of the blue, Jason convinced me we had to combine them into one. It wasn't until years later, I found out why. It was because no one wanted to come to mine. And Jason didn't want me to know. He protected me. Every single day. I wish, that day at the river, I had protected him. I'm so sorry, Jay-Jay. We failed you. All of us.||”|
|— Cheryl at Jason's memorial[src]|
Jason was the son of Clifford and Penelope Blossom, and the twin brother of Cheryl Blossom. He was captain of the school water polo team and a member of the Riverdale Bulldogs. He supposedly died under mysterious circumstances when he fell from a boat into Sweetwater River on July 4th, prior to the start of the series. But as it turns out, he died a week later around July 11th when he was shot by an unknown assailant. He is also the late father of Polly's soon to be born twin babies.
Jason grew up in Riverdale, alongside his twin sister, Cheryl Blossom. Prior to the start of the series, he was in a relationship with Betty Cooper's sister, Polly. According to Betty, he meant the world to her but she meant nothing to him. The relationship ended badly, Cheryl speculated that Jason was likely the reason that Polly suffered a nervous breakdown and was sent to live in a group-home.
When Jason and Cheryl were younger, their mother would take them upstairs into their rooms, where she would tell them bedtime stories about the Sugarman, her very own concocted version of a child's Bogeyman, in an attempt to turn an all-too-real monster into something less. Little did Jason know at the time, the Sugarman was real, and looking to protect them from the danger that followed was their mother, who sent Jason and Cheryl into their rooms whenever he would visit Thornhill.
After Fred Andrews suffered a gun shot wound during a supposed robbery at Pop's Chock'lit Shoppe, Fred had a number of odd dreams during his drift in and out of consciousness, one of which included Jason, who sat in the crowd, alongside his father, as Archie and Veronica's got married.
Jason was a moderately slim young man of medium stature, around 6' 1", with pale skin, red hair and steel blue eyes. Ironically, despite his leading position on the Riverdale Bulldogs, he was not an especially muscular individual. He was often seen wearing his blue and gold varsity jacket though. According to Veronica Lodge, Jason was "crazy handsome", Cheryl agreed, saying that he was the "handsomest".
As Jason was killed prior to the start of the series, not much information about his personality is known. He did bully Jughead at school from time to time. However, according to Cheryl, he was the best brother anyone could've asked for, and was a genuinely nice person who didn't deserve to be tortured and murdered. Jason was very protective of his loved ones, especially Cheryl. When they were younger, Cheryl insisted on having separate birthdays from Jason despite the fact that they were twins, until one year, he randomly recommended that they combine their birthdays into one. It was not until years later that Cheryl discovered the reason for this was that no one would come to her birthday. Jason protected her feelings whenever he thought it was needed.
- Jason was in an independent study program with Geraldine Grundy while at Riverdale High School. She considered him to be inspirational.
- After his body is found, Jason Blossom is buried in the cemetery on the grounds of Thornhill. Prior to the discovery of his body, his parents buried an empty casket.
- According to Cheryl, Jason always adored the drive-in.
- Jason is older than Cheryl by three minutes.
- Jason has never spoken on-screen.
- See also: Category:Images of Jason Blossom