Sgt. James Conover / Major Harold Giles
Emmett Balfour / Professor Hebbel
Trent / Paul Cameron
Adam Ballard / Louis Mace
Chief of Staff / Coulter
Bill Turner / Coroner Leland
Dean Radcliffe / Mr. Terrence
Detective Lt. Runyan / Dr. Paul Fredericks (uncredited)
Philip Exeter Dundee / Elder of Luminos
Dr. Paul Pollard / Bert Hamil
Randolph E. Branch / New Sentry
Lt. Rupert Lawrence Howard (uncredited) / James Custer
Ben Fields / Lincoln Russell
Harvey Kry Jr. / Capt. Terrence Ralph Brookman
Chino Rivera / General Juan Mercurio
Aabel / Dr. Block
Policeman / Navigator Dexter
The Mikie / Thetan (uncredited)
Richard Bellero / Andro
Yvette Leighton / Ann Barton
Prof. Stephanie Linden / Ann Pearson
Akada / Dr. Sui-Lin
Dave Crowell / Luis B. Spain
Henry Castle / Galaxy Being (as Wm. O. Douglas)
