Doc Hammer
Dr. Girlfriend / Henchman 21 (voice) (81 eps)
Christopher McCulloch
Hank Venture / The Monarch (voice) (81 eps)
Patrick Warburton
Brock Samson (voice) (81 eps)
James Urbaniak
Dr. Venture (voice) (81 eps)
Michael Sinterniklaas
Dean Venture (voice) (81 eps)
Steven Rattazzi
Dr. Orpheus (voice) (31 eps)
Lisa Hammer
Triana Orpheus (voice) (17 eps)
Cristin Milioti
Sirena (voice) (16 eps)
Paul Boocock
Dr. Jonas Venture (voice) (15 eps)
Brendon Small
Action Johnny (voice) (9 eps)
Dana Snyder
The Alchemist (voice) (3 eps)
Bill Hader
Professor Impossible / Phage (voice) (3 eps)
Toby Huss
General Treister (voice) (3 eps)
H. Jon Benjamin
The Master (voice) (2 eps)
Stephen Colbert
Professor Impossible (voice) (2 eps)
Kevin Conroy
Captain Sunshine (voice) (2 eps)
Charles Parnell
Jefferson Twilight (voice) (2 eps)
Patton Oswalt
Wonderboy (voice) (1 eps)
Nathan Fillion
Brown Widow (voice) (1 eps)
Seth Green
Lance Hale / Mrs. Z (voice) (1 eps)
Steve Park
Mike Sorayama (voice) (1 eps)
John Hodgman
Dale Hale (voice) (1 eps)
Gillian Jacobs
Marsha Backwood (voice) (1 eps)