A background character during the first season in the cafeteria, the prototype version of Jason first appeared in "Cartman Gets an Anal Probe", but afterward was seldom seen. A revised, different design was prominent in the first part of the episode "South Park is Gay!", seen with Craig's Gang, where he is part of their metrosexual gang along with Craig Tucker, Token Black, and Tweek Tweak. He was also part of the group who helped recover the "future telling device" in "Marjorine", waiting with Timmy outside the containment center for the rest of the boys to return.
Jason has brown hair with sideburns and a high forehead, and wears a purple top and a pair of blue jeans, which were originally dark gray. In "The Hobbit", Wendy mentions that he has freckles. His character is based on Jason McHugh, who was featured with Trey Parker and Matt Stone in "Cannibal! The Musical" and "Orgazmo".
Jason on South Park Studios.
Jason receiving a rose after making it to the second round.
Jason being eliminated as a candidate in the third round.
Jason angry at Kevin Stoley in "The Return of the Fellowship of the Ring to the Two Towers"
Jason, as Legolas, from behind.
Jason building the room for the 'future telling device' in "Marjorine"
Jason arguing with the other boys about who gets to use the device first.
Jason hunting a leprechaun in "Imaginationland".
Jason about to see how he ranks in attractiveness, according to the girls, in "The List".
Jason singing and dancing in "Elementary School Musical".
Jason as a basketball player in "Elementary School Musical"
Jason on the floor about to watch Terrance and Phillip.
Jason meeting with Cartman and other children in "It's a Jersey Thing"
Jason from the side in "It's a Jersey Thing"
Jason and the other boys in "Douche and a Danish"
Jason's friendships are ill-defined - he is seen talking with Kevin Stoley often, implying a possible friendship. He was a part of Craig's metrosexual "gang" in "South Park is Gay!", but has not been part of Craig's Gang since then. In recent seasons, Jason has been seen sitting with the Boys at lunch, but he is sometimes swapped for Tweek Tweak or Kevin Stoley. In several episodes he is seen sitting by Fosse and a number of unknown children. Starting in "Butters' Bottom Bitch", he is frequently seen sitting with Scott Malkinson and several unknown students in the cafeteria.
- He was ranked #5 in the list of most attractive boys by the girls in "The List", however the list was fake.
- A person looking similar to Jason was seen in the 5th grade line in "Lice Capades".
- "Professor Chaos" - Is one of the contestants to be the new 4th member and replacement of Kenny in the group.
- "The Return of the Fellowship of the Ring to the Two Towers" - Is seen glaring at Kevin as he walks away after being ostracized at the boys' LOTR council, wherein Jason plays Legolas.
- "South Park is Gay!" - Part of Craig's competing metrosexual gang; first speaking role and first episode as a member of the fourth-grade class at South Park Elementary
- "Raisins" - Appears in the Raisins Restaurant.
- "Quest For Ratings" - Seen in the background in a flashback.
- "Stupid Spoiled Whore Video Playset" - While walking with Tweek, Sally tells the other girls that he has "a huge bulge." Annie also thinks that the two "would make a great three-way".
- "Mr. Garrison's Fancy New Vagina" - One of the boys amazed at Kyle's negroplasty.
- "Marjorine" - One of several boys that take part in the plan to capture the "Cootie Catcher."
- "Make Love, Not Warcraft" - Jason helps the boys fight the rogue player online.
- "Imaginationland" - Part of Cartman's group that hunts for a leprechaun in the beginning of the episode
- "The List" - Shown to have ranked in the fifth spot on the corrupted list.
- "Breast Cancer Show Ever" - Is seen as part of Wendy's entourage as she prepares to fight Cartman.
- "Elementary School Musical" - Sings in the opening musical number and plays on the basketball team.
- "Eat, Pray, Queef" - Seen at Cartman's house getting ready to watch 'Blood Rage: Part 2'.
- "It's a Jersey Thing" - Part of Cartman's entourage.
- "1%"- Seen at the assembly.
- "Faith Hilling" - Seen in the memeing class with the other 4th Grade students.
- "Jewpacabra" - Seen at the Easter egg hunt.
- "Butterballs" - Seen in the background in the cafeteria, in the hallways, and participated in Stan's anti-bullying video.
- "Cartman Finds Love" - Seen in the background in the school's hallways and in the boy's locker room.
- "Sarcastaball" - Plays football and sarcastaball with the other boys.
- "A Scause For Applause" - Seen in the background in the school hallways.
- "Let Go, Let Gov" - Seen eating in the cafeteria.
- "Titties and Dragons"- Seen at Red Robin.
- "The Hobbit" - Walks past Wendy and Stan in the hallway and stops to listen after Wendy points out that he has freckles.
- "Gluten Free Ebola"- Seen in the background in the hallway
- "Stunning and Brave"- Seen at the school meeting and in the hallway; during the meeting, Jason is seen with two adults, presumably his parents.
- "The City Part of Town"- Seen as part of the children's choir at the opening of the South Park Whole Foods.
- "You're Not Yelping"- Seen in the hallway.
- "Sponsored Content"- Seen in the hallway.
- "Truth and Advertising"
- "PC Principal Final Justice"- Seen at the school assembly.
- "Member Berries"- Seen at the school assembly.
- "Wieners Out" - Seen participating in Butters' Wieners Out movement.
- "Douche and a Danish" - Seen in the battle between the boys and the girls.
- "Oh, Jeez" - Seen at the school assembly.
Jason plays a minor role in the game as a member of the Drow Elves, tending the armory at the Elven Kingdom. You have to buy equipment from him to befriend him. This is one of the few times he speaks, and the only time you interact with him in the game.