J.D. Roth
Jonny Quest (voice) (26 eps)
Jesse Douglas
Jessie Bannon (voice) (26 eps)
Michael Benyaer
Hadji Singh (voice) (26 eps)
George Segal
Dr. Benton Quest (voice) (26 eps)
Robert Patrick
Race Bannon (voice) (26 eps)
Michael Bell
Ezekiel Rage (voice) (4 eps)
Ed Gilbert
Professor Scheele (voice) (3 eps)
Jim Cummings
Florid Face (voice) / Yagor (voice) / Captain James (voice) (3 eps)
Jim Meskimen
Torgeson (voice) (3 eps)
Chick Vennera
Gustavo Arollo (voice) (3 eps)
Mayim Bialik
Julia (voice) (2 eps)
David Ackroyd
Ezekiel Rage (voice) (2 eps)
Paul Eiding
Bennett (voice) (2 eps)
Helene Udy
Natasha Rastova (voice) (2 eps)
Michael Horse
Ames (voice) (2 eps)
Earl Boen
Officer (voice) / Stage Coach Guard (voice) (2 eps)
Nick Jameson
Leif (voice) (2 eps)
B.J. Ward
Iris the Computer (voice) (2 eps)
Jeffrey Tambor
Black Jack Lee (voice) (1 eps)
Jeff Bennett
Gun Captain (voice) / Diver (voice) (1 eps)
Mark L. Taylor
Brother James (voice) (1 eps)
Paxton Whitehead
Commander (voice) (1 eps)
Nick Tate
Pirate (voice) (1 eps)
Mark Hamill
Eldoradoan (voice) (1 eps)
Alex Dent
Indian Boy (voice) (1 eps)
Nancy Travis
Captain Spencer (voice) (1 eps)
Dorian Harewood
Officer (voice) (1 eps)
Brock Peters
Masai (voice) (1 eps)
Tristan Rogers
Hawkins (voice) (1 eps)
Charlie Adler
Rawlings (voice) (1 eps)
Jennifer Hale
Kate (voice) (1 eps)
Lewis Arquette
Civilian (voice) / Driver (voice) (1 eps)
Tara Strong
Kazrina (voice) (1 eps)
Carolyn Seymour
Aleutian Woman (voice) / Mother (voice) (1 eps)
Dee Bradley Baker
Dr. Vedder (voice) (1 eps)
Darleen Carr
Abby (voice) (1 eps)
Haven Hartman
Karla (voice) (1 eps)
Paul Mercier
Diver (voice) / Technician (voice) (1 eps)
Larry Moss
Skipper (voice) (1 eps)
Clive Revill
Harpooner (voice) / Medical Officer (voice) (1 eps)
George Ball
Announcer (voice) (1 eps)
Megan Cavanagh
Julia (voice) (1 eps)
Jan Rabson
Avary (voice) / Donaldson (voice) (1 eps)
Peter Renaday
High Lama (voice) (1 eps)