Sterling Beaumon had originally auditioned for Spud. His improvisational abilities and hyperactive approach to the character led to him being cast instead as Cody. Most of his lines in the film are improvised.
Dalton O'Dell was cast as Spud after Dominic Scott Kay backed out due to scheduling conflicts. One of the main reasons O'Dell was cast was that he reminded writer/director Tyler Norman of a young Jonathan Brandis.