Spencer Klein (10)

Arnold (voice)

Francesca Marie Smith (11)

Helga Pataki (voice)

Jamil Walker Smith (14)

Gerald Johanssen (voice)

Blake McIver Ewing (11)

Eugene Horowitz (voice)

Olivia Hack (13)

Rhonda Wellington Lloyd (voice) / Rhonda Wellington Lloyd / Mary (voice)

Phillip Van Dyke (12)

Arnold (voice) / Ludwig (voice)

Justin Shenkarow (15)

Harold Berman (voice) / Harold Berman(voice) / Harold Berman / Robert (voice) / Harold Berman / Iggy (voice) / Harold Berman / Boy on Bicycle (voice) / Joey (voice) / Harold Berman (voice; uncredited)

Christopher Walberg (10)

Stinky Peterson (voice) / Stinky Peterson / Kyle (voice) / Stinky Peterson / Bratty Kid #1 (voice) / Stinky Peterson (voice; uncredited) / Stinky (voice)

Lane Toran (13)

Arnold (voice) / Wolfgang (voice) / Wolfgang / French Boy (voice) / Arnold (singing voice)

Dan Castellaneta (38)

Grandpa Phil (voice) / Grandpa Phil / Grandpa Phil's Father / Jolly Olly Man (voice) / Grandpa Phil / Cop #1 (voice) / Delivery Man (voice) / Grandpa Phil / Judge (voice) / Animal Control Officer (voice) / Grandpa Phil / Chicken Man (voice) / Grandpa Phil / Nick Vermicelli (voice) / Big Arnold (voice) / Grandpa Phil / Nolo (voice) / Grandpa Phil / Reporter (voice) / Nick Vermicelli (voice)

Anndi McAfee (17)

Phoebe Heyerdahl (voice) / Phoebe Heyerdahl / Clerk (voice) / Patrice (voice) / Phoebe Heyerdahl / Kid #2 / Phoebe Heyerdahl / Italian Girl / French Girl (voice) / Phoebe Heyerdahl / Girl (voice) / Phoebe Heyerdahl / Worker #2 (voice) / Phoebe Heyerdahl / Ruth P. McDougal (voice) / Phoebe Heyerdahl / Woman (voice) / Phoebe Heyerdahl / Joy (voice)

Michael Welch (9)

Unknown

Haley Joel Osment (8)

Unknown

Jess Harnell (32)

Unknown

Jeremy Suarez (6)

Unknown

Henry Gibson (61)

Unknown

Jack Angel (65)

Unknown

Andy Dick (30)

Monkeyman (voice)

Fred Willard (63)

Unknown

Pat Corley (66)

Unknown

Mayim Bialik (20)

Maria (voice)

Zelda Rubinstein (63)

Unknown

Georgia Engel (48)

Unknown

Michael McKean (48)

Unknown

Kathie Lee Gifford (43)

Unknown

Elizabeth Ashley (57)

Mrs. Vitello (voice)

Brian Doyle-Murray (50)

Lasombra

Davy Jones (50)

Himself

Michael Levin

Ray Doppel (voice)

Steven Hartman

Curly (voice)