Billy (voice) (1 episode)
Billy / Mogar / Rodney J. Squirrel (voice) (1 episode)
Various Characters (1 episode)
Alpha (voice)
Snap (voice)
Billy (voice)
Writer
Moxxie (voice) (20 episodes)
Zim (voice)
Additional Voices (voice)
Pacifier / Jerry / Bear (voice) (1 episode)
Stevey Murple (voice) (1 episode)
Gormal MacGuffin (voice)
Kaos (voice) (38 episodes)
Lugosi (voice) (65 episodes)
Imp (voice) (1 episode)
Mixadel (1 episode)
Scrud, Splasho (1 episode)
Munchkin Suitor (voice)
Orange Haired Elf (voice)
Fryborg / Big Cheese / Salty Pup (voice) (10 episodes)
Grey Matter / Dispatcher (voice)
Lowe's Salesman #3
Book Store Autoraph Hound
Bob Zaiderman
Billy / Harold / Pumpkin / Trick-or-Treater Eater (voice)
Grey Matter
Billy / Harold (voice)
Sheldon Goldstein
Grey Matter / Stinkfly Prisoner (voice)
Billy / Billy's Dad (voice)
Billy / Billy's Dad (voice)
Billy / Billybot / Harold / Pale Ghoulish Juror / Chippy the Squirrel (voice) (as Richard Horvitz)
Dudley / Guard (voice) (1 episode)
Waaa Baby
Grey Matter (voice) (21 episodes)
Billy (voice) (as Richard Horvitz)
Otis (voice)
Chuck (voice) (1 episode)
ADR Voice Casting
Ned Frishman / Guard / Vicious Looking Warrior (voice) (1 episode)
Ned Frischman (voice) (1 episode)
Billy/Guy (voice)
Jimmy Osgood (voice) (1 episode)
Scooper (voice) (uncredited)
Mitchey Mekelburg (voice) (1 episode)
Billy (voice) (184 episodes)
Writer (2 episodes)
Additional Character Voices (voice)
Puppy in Barn (voice)
ADR & Dubbing
Zim (voice) (46 episodes)
Danny
Cheddar (voice)
Stonehenge (voice)
Additional Voices (voice)
Elevator Passenger (2 episodes)
Smaller Chair (voice) (1 episode)
Duck Head (voice) (1 episode)
Beaver #2 / Owl #1 (voice) (1 episode)
Daggett (voice) (123 episodes)
Alpha 5 (voice)
Alpha 5 (voice)
Capricorn (as Richard Stults)
Daggett Beaver
Young Energizer
Howie Buchanan (2 episodes)
Alan Eakian