Harvey Birdman, Attorney at Law/Trivia
- ~Hey, It's That Voice!~ (Stephen Colbert as Phil Ken Sebben)
- Stephen Colbert as Reducto.
- Lewis Black as Elliott the Deadly Duplicator.
- Peter MacNicol as X the Eliminator.
- Michael McKean as Spyro.
- Lumbergh plays Harvey himself (and Mightor).
- Birdgirl is voiced by Paget Brewster (who was also Ms Indestructible in The Specials).
- Toby Huss played Ernie Devlin and Shado The Brain Thief.
- Grey DeLisle as Debby
- Maurice LaMarche as Fred, Yogi, Quick Draw McGraw, Speed Buggy, and others
- Tress MacNeille as Wilma and Pebbles
- Tom Kenny as Boo Boo and Top Cat