Jay Leno was the host of The Tonight Show with Jay Leno from 1993 until 2009, later returning in 2010, and had his final show on February 6, 2014. He first appeared in the Jay Leno Short, voiced by himself, where he spoke to the children of South Park about Thanksgiving, only to hear jokes regarding his chin.
He later reappeared in "Fishsticks", spreading the infamous joke. He was redesigned and Trey Parker now played his part. He also appeared in the episode "Funnybot" as one of the angry comedians, even threatening to kill Kenny McCormick with a bullet through the head.
Though his chin is portrayed rather large (as it is in real life) in most of his appearances, it is far larger in "City on the Edge of Forever (Flashbacks)" than in any episode before or after.
Jay Leno is most notable for his large chin and is drawn as a South Park character with an exaggerated chin. He wears a black suit, a white shirt, and black shoes. In the Jay Leno Short, his tie was black but in "Fishsticks" he had a red tie. His hair color was originally dark brown but has since grayed significantly leaving only a small patch of brown left.