In the scene where Solomon's eating spagetti in the bath, there's a piece of bacon taped to the wall behind him. Says Werner Herzog: "When I saw a piece of fried bacon fixed to the bathroom wall in Gummo, it knocked me off my chair. [Korine's] a very clear voice of a generation of filmmakers that is taking a new position. It's not going to dominate world cinema, but so what?"
Other cast members were recruited during the film's lengthy pre-production period. Harmony Korine often approached people on the street, in bowling alleys and in fast food restaurants, and asked them to play a part in his movie.
In the screenplay, Bunny Boy talks, but only during the scene in the swimming pool. He also explains why he has the word MAC tattooed on his fingers: "My parents like to call me that. Mac spelled backward is Cam. Cam is their favorite car... Camaro." He also claims he was born with one fully grown tooth, and his parents "wanted to name me Plak."
Despite having top billing in the opening credits, Linda Manz's first appearance in the film occurs at approximately 43 minutes in. Additionally, her total screen time accumulates to around 4 and a half minutes.