- Chris Sanders as Stitch, the main protagonist of the film, who dreams of being a video game warrior.
- Ron Allen as BJ, the deutergonist of the film, a blue transforming race car robot with a frog-like face and Stitch's best friend.
- Neil Patrick Harris as Hermit the Gator, the secondary deutergonist of the film, a green alligator, and Stitch's second friend.
- Jessica Chastain as Princess Angel, a warrior princess who becomes Stitch's love interest.
- Bruce Campbell as King Mechanic, the corrupt ruler of Steel Rush who flirts with Princess Angel.
- Adam Carolla and Eric Schussler as Genetic and Metal, King Mechanic's robot guards.