Nat Faxon

Captain Underpants / Mr. Krupp (voice)

Jay Gragnani

Harold (voice)

Ramone Hamilton

George (voice)

Sean Astin

Narrator (voice)

Dayci Brookshire

Jessica / Dressy (voice)

Jim Cummings

Santa (voice)

Jorge Diaz

Melvin / Stanley Peet (voice)

Peter Hastings

Comic Narrator (voice)

Evan Kishiyama

Steve 'Gooch' Yamaguchi (voice)

David Koechner

Mr. Meaner (voice)

Erica Luttrell

Erica / George's Mom (voice)

Patty Mattson

Miss Anthrope / Harold's Mom (voice)