Johnny Depp felt bad about having to ridicule Darlene Cates' character, "Momma," and would often apologize to her after shooting. Depp once said to Cates, "Man, I want you to know how much I hated having to say those things about you, or about your character."
Leonardo DiCaprio played the part of Arnie Grape so well that when he showed up for the film's premiere, many people were shocked and astonished to learn that the young actor was not actually mentally disabled.
Mary Steenburgen was the only person confident enough in Leonardo DiCaprio's performance that she was willing to pay him from her own salary.
When getting into character, Leonardo DiCaprio remarked of it, "I had to really research to get into the mind of somebody like that. I spent a few days at a home for mentally unstable teens. We just talked and I watched their mannerisms. People have these expectations that mentally retarded children are really crazy, but that isn't so. It's refreshing to see them, because everything's so new to them."