Michael McKean as Mr. Bream (voice)

Courtland Mead as Gustav Patten 'Gus' Griswald (voice)

Ashley Johnson as Gretchen Grundler (voice)

Jason Davis as Mikey Blumberg (voice)

James Earl Jones as Mister (voice)

Rickey D'Shon Collins as Vincent Pierre 'Vince' LaSalle (voice)

Andrew Lawrence as Theodore J. 'T.J.' Detweiler (voice)

Bobbi Page as Chorus (singing voice) (uncredited)

Ross Malinger as T.J. Detweiler (archive sound)

Pamela Adlon as Ashley Spinelli

Allyce Beasley as Miss Alordayne Grotkey

April Winchell as Miss Muriel P Finster

Dabney Coleman as Principal Peter Prickly

Gregg Berger as Robotic Santa/TV Editor/Astronaut

Klee Bragger as Digger Sam

Dick Clark as Dick Clark

Rachel Crane as Ashley Q

E. G. Daily as Trisha/Cap'n Sticky/Mall Elf/Kid #2

Paul Dooley as Hank the Janitor/Mall Santa

Blake McIver Ewing as Menlo

Robert Goulet as Mikey Blumberg

Jess Harnell as Ricky McCloud

Tress MacNeille as (voice)

Anndi McAfee as Ashley A (voice)

Sam McMurray as (voice)

Ryan O'Donohue as Randall Weems/Digger Dave

Katey Sagal as Flo Spinelli

Ronnie Schell as Mayor Fitzhugh

Michael Shulman as Hustler Kid

Francesca Marie Smith as Ashley B (voice)

Erik von Detten as Erwin Lawson

Frank Welker as Animal voices