Phillip Van Dyke

Arnold (voice)

Jamil Walker Smith

Gerald Johanssen (voice)

Francesca Marie Smith

Helga Pataki (voice)

Anndi McAfee

Phoebe Heyerdahl (voice)

Justin Shenkarow

Harold Berman (voice)

Christopher Walberg

Stinky Petersen (voice)

Adam Wylie

Curly Gammelthorpe (voice)

Steve Viksten

Oskar Kokoshka / Smitty (voice)

Mary Scheer

Suzie Kokoshka (voice)

Dom Irrera

Ernie Potts (voice)

Baoan Coleman

Mr. Hyunh (voice)

Lou Rawls

Harvey (voice)

Maurice LaMarche

Douglas Cain / Big Bob Pataki (voice)

Dan Castellaneta

Grandpa Phil / Additional Voices (voice)

Tress MacNeille

Arnold's Grandma (voice)

Jamie Mitchell