Andrew Lawrence
T.J. Detweiler (voice)
Rickey D'Shon Collins
Vince La Salle (voice)
Pamela Adlon
Spinelli (voice)
Ashley Johnson
Gretchen Grundler (voice)
Jason Davis
Mikey Blumberg (voice)
Courtland Mead
Gus Griswald (voice)
April Winchell
Ms. Finster / Mrs. Detweiller (voice)
Dabney Coleman
Principal Peter Prickly (voice)
Ryan O'Donohue
Digger Dave / Randall (voice)
Robert Goulet
Mikey's Singing Voice (voice)
Melissa Joan Hart
Becky (voice)
Peter MacNicol
Fenwick (voice)
Tony Jay
Dr. Rosenthal (voice)
James Woods
Dr. Phillium Benedict (voice)
Andrea Martin
Lunchlady Harriet (voice)
Tress MacNeille
Lunchlady Irma / Ms. Lemon / Opera Director / Dr. Steinheimer (voice)
Nicholas Turturro
Cop #1 (voice)
Kevin Michael Richardson
Cop #2 (voice)
Dan Castellaneta
Guard #1 (voice)
Diedrich Bader
Guard #2 (voice)
Kath Soucie
Counselor (voice)
Charles Kimbrough
Mort Chalk (voice)
Robert Stack
Superintendent (voice)
Ken Swofford
Coach (voice)
Francesca Marie Smith
Ashley B / Swinger Girl / Upsidedown Girl (voice)
Erik von Detten
Captain Brad Lawson (voice)
Paul Willson
Coach Kloogie / Mr. Detweiler (voice)
Patrick Renna
Jordan (voice)
Anndi McAfee
Ashley A (voice)
Lane Toran
King Bob (voice)
Rachel Crane
Ashley Q (voice)
Klee Bragger
Digger Sam (voice)
R. Lee Ermey
Colonel O'Malley (voice)
Clyde Kusatsu
Mr. Yamashiro (voice)
Clancy Brown
Bald Guy (voice)
Allyce Beasley
Miss Grotke (voice)
Gregg Berger
Tech #1 (voice)
Elizabeth Daily
Cap'n Sticky (voice)
Ron Glass
Dr. Lazenby / Tech #2 (voice)
Mark Robert Myers
Technician (voice)
Phil Proctor
Golfer #2 / Scientist #2 (voice)
Justin Shenkarow
Soldier Kid / Wrestler Kid (voice)
Michael Shulman
Hustler Kid (voice)
Katey Sagal
Mrs. Flo Spinelli (voice) (uncredited)