Donnie Stevens (voiced by Nick Spano) is the eldest child and first son of Steve and Eileen Stevens. While not an exceptionally smart boy, Donnie is shown to excel in athletics and seems to have shades of the "big brother instinct." While most of his story lines revolve around his sports and dating, occasionally he will become involved in whatever is going on with his younger siblings. In "Scrub Day," he left in the middle of his history pageant to go to the middle school and come to Louis's aid. Also in "Battle of the Bands" he tries to keep Ren from going to a high school party.
In the epilogue scene of the movie, Louis, who narrates the scene, tells the audience that Donnie moved on to college and continued to succeed in sports. Since in this scene he is shown with a suitcase, it can be assumed that he chose to live on campus.