Nat Faxon
Captain Underpants / Mr. Krupp / Buffalobe (voice)
Jay Gragnani
Harold Hutchins (voice)
Ramone Hamilton
George Beard / Young Mr. Cleveland (voice)
Sean Astin
Narrator / Putter Mulligan (voice)
Dayci Brookshire
Jessica / Dressy / Smartaconda (voice)
Jorge Diaz
Melvin / Stanley Peet (voice)
Todd Grimes
Benjamin Franklin (voice)
Peter Hastings
Comic Narrator / Marlin (voice)
Evan Kishiyama
Steve 'Gooch' Yamaguchi (voice)
David Koechner
Mr. Meaner (voice)
Phil LaMarr
Mr. Cleveland / Viper Chai (voice)
Erica Luttrell
Erica (voice)
Patty Mattson
Miss Anthrope (voice)
Brennan Murray
Bo Hweemuth (voice)
