*Gil Gerard as Capt. William "Buck" Rogers
- Erin Gray as Col. Wilma Deering
- Thom Christopher as Hawk
- Jay Garner as Admiral Efram Asimov
- Wilfrid Hyde-White as Dr. Goodfellow
- Barbara Luna as Koori
- Lance LeGault as Flagg
- David Opatoshu as Llamajuna
- Sid Haig as Pratt
- Kenneth O'Brien as Captain
- Felix Silla as Twiki
- Dennis Haysbert as Communication Officer
- Lavelle Roby as Thromis
- Michael Fox as High Judge
- Andre Harvey as Thordis
- Chris O'Connor as Young Lieutenant
- Timothy O'Keefe as Bailiff
- Ken Chandler as Court Clerk
- Susie Ewing as Simmons
- Jeff David as Voice of Crichton (uncredited)
- Bob Elyea as Voice of Twiki (uncredited)