Michael Angarano as Will Stronghold

Mary Elizabeth Winstead as Gwen Grayson / Royal Pain

Kurt Russell as Steve Stronghold / The Commander

Kelly Preston as Josie Stronghold / Jetstream

Danielle Panabaker as Layla Williams

Bruce Campbell as Coach Boomer

Lynda Carter as Principal Powers

Kevin Heffernan as Ron Wilson, Bus Driver

Dee Jay Daniels as Ethan

Kelly Vitz as Magenta

Loren Berman as Little Larry

Nicholas Braun as Zachary "Zach" Braun / Zack Attack

Steven Strait as Warren Peace

Malika as Penny

Khadijah Haqq McCray as Penny

Jake Sandvig as Lash

Will Harris as Speed

Dustin Ingram as Carbon Copy Kid

Christopher Wynne as News Anchor

Cloris Leachman as Nurse Spex

Jim Rash as Mr. Grayson / Stitches

Dave Foley as Mr. Boy

Kevin McDonald as Mr. Medulla

Amy Brown as Twin

Kimmy Brown as Evil Twin

Lucille Soong as Cook

Zachry Rogers as Young Commander

Tom Kenny as Mr. Timmerman

Jill Talley as Mrs. Timmerman

Patrick Warburton as Royal Pain (voice)

Vakisha Coleman as Student Sidekick (uncredited)

Sean Gordon as Penny's Date (uncredited)

Hans Hernke as Laser-Vision Boy (uncredited)

Jason Maxim as Funky Prom Boy (uncredited)