A boy resembling Bart (presumed to be Bart himself) appears in "Cartoon Wars Part II". He mentions historical moments from Bart's life and assisted Cartman to try to cancel Family Guy and convince FOX Network to stop airing the show.
When Kyle arrives to stop Cartman, Bart knocks him out with his skateboard. After hearing one of Kyle's "gay little speeches", Bart instead decides to help save Kyle and Family Guy.
In "Cartoon Wars Part II", Bart has blond spiky hair and wears a red T-shirt, blue pants, and blue and white shoes. In "The Problem with a Poo", Bart's appearance has finally starting to resemble the actual self, but with yellow skin and wears an orange T-shirt, green pants, and red and white shoes.
On The Simpsons, Bart is usually portrayed as mischievous, rebellious, and cunning, but with a good heart. On South Park, he is portrayed similarly, but may be somewhat more bad-intentioned and destructive, as he stated that he could do terrorism. Additionally, Bart later helped Cartman with said terrorism by knocking out the clearly good-intentioned Kyle with his skateboard, then helped keep him trapped. However, Kyle does seemingly convince him to free him so he can stop Cartman by telling him something about becoming as bad as he is, likely indicating more moral responsibility. He also seems to strongly dislike Family Guy.
- Unlike his appearance on The Simpsons, Bart's hairline is slightly more yellow than his skin on South Park. However, his hair color is more beige than on The Simpsons.
- Bart is voiced by a female actress (Nancy Cartwright) on The Simpsons. Similarly, he is also one the of few male characters on South Park to also be voiced by a woman.
- Bart is based on Matt Groening, just like how Kyle and Stan are based on Matt Stone and Trey Parker.