Hey Arnold!

Francesca Marie Smith

Helga Pataki (voice)

Jamil Walker Smith

Gerald Johanssen (voice)

Dan Castellaneta

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

Justin Shenkarow

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

Anndi McAfee

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

Christopher Walberg

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

Phillip Van Dyke

Arnold (voice), Ludwig (voice)

Spencer Klein

Arnold (voice)

Olivia Hack

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

Lane Toran

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

Sam Gifaldi

Sid (voice), Sid / Robert (voice), Billy (voice)

Blake McIver Ewing

Eugene Horowitz (voice)