•
Norman Alden –
Aquaman, Caller, Professor Rogers (in "Will the World Collide?"), Gruth (in "The Ghost"), Earthor #1 (in "Invasion of the Earthors") •
Jack Angel –
Hawkman,
Samurai, Dr. Lau (in "Time Rescue") •
Michael Bell –
Zan, Gleek, Mechanic (in "Joy Ride"), Jeff (in "Joy Ride"), Kalmo (in "The Mysterious Time Creatures"), Sully (in "Runaways"), Gary •
Wally Burr –
Atom, Secret Four Member #1 (in "The Secret Four"), The Enforcer (in "The Enforcer"), Peterson (in "The Invisible Menace"), Dr. Pisces (in "Attack of the Giant Squid"), Newton's son (in "The Collector"), Zeno Leader (in "Exploration Earth"), Lionex (in "The Lion Men"), Bus Depot Master (in "Runaways") •
Ted Cassidy – Crag the Earthor (in "Invasion of the Earthors") •
Henry Corden – Vika (in "Tibetan Raiders"), Rudolph Korloff (in "The Mummy of Nazca") •
Regis Cordic –
Manta,
Apache Chief (first appearance), Nemus (in "The Invisible Menace"), Professor Martinez (in "The Water Beast"), Jules (in "The Marsh Monster") •
Danny Dark –
Superman •
Shannon Farnon –
Wonder Woman,
Rima,
Hawkgirl, Drowning Boy, Newton's daughter (in "The Collector"), Dr. Amy Zahn (in "The Fifty Foot Woman"), Dr. Taylor (in "The Fifty Foot Woman") •
Pat Fraley – Ron (in "Handicap"), Jack (in "Cheating") •
Bob Hastings – Corky (in "Joy Ride"), Scott (in "Handicap") •
Buster Jones –
Black Vulcan • Jane Jones – Suzie (in "Tiger on the Loose"), Jody (in "Hitchhike") •
Casey Kasem –
Robin, Police Officer (in "The Brain Machine"), Tour Guide (in "Invasion of the Earthors"), Mr. Brown, Guest, Justice League Computer, Secret Four Member #3 (in "The Secret Four"), Dictor (in "The Mysterious Time Creatures"), Insecta (in "Coming of the Antropods"), Brunette Scientist (in "The Marsh Monster"), Mr. Thompson (in "Doctor Fright"), Professor Larvey (in "Will the World Collide?) • Joyce Mancini – Mary Nelson (in "Tiny World of Terror") •
Ross Martin – Dr. Cranum (in "The Brain Machine"), Professor Strickland (in "Tiny World of Terror") • Chuck McClennan – Mongor (in "City in a Bottle") •
Alan Oppenheimer – Doctor Fright (in "Doctor Fright"), Wolfman (in "The Man Beasts of Xra"), The Marsh Monster (in "The Marsh Monster"),
Gentleman Ghost (in "The Ghost"), Scientist (in "The Ghost") •
Richard Paul – Professor Price (in "Forbidden Power") •
Barney Phillips –
Flash (in "Tibetan Raiders"), Jules (in "The Marsh Monster") •
Robert Ridgely - Captain Shark (in "The Protector") •
Mike Road – Varko (in "Planet of the Neanderthals") •
Michael Rye – Apache Chief,
Green Lantern, Abominable Snowman (in "Alaska Peril") •
Ronnie Schell – First Mate (in "The Whirlpool") •
Olan Soule –
Batman, Police Officer (in "The Brain Machine"), Secret Four Member #4 (in "The Secret Four") Professor Wong (in "Tiny World of Terror"), Professor Fearo (in "Will the World Collide?") •
John Stephenson – Police Officer (in "Doctor Fright"), Dr. Droid (in "The Monster of Dr. Droid"), Pantherman (in "The Man Beasts of Xra"), Sculpin (in "Frozen Peril"), Freighter Captain (in "Frozen Peril") •
Robert Towers – Hydronoid Captain (in "Invasion of the Hydronoids") •
Jean Vander Pyl – Medula (in "The Mind Maidens"), Dr. Xra (in "The Man Beasts of Xra"), Magda Duval (in "The Marsh Monster") • Louise "Liberty" Williams –
Jayna, Little Sister •
Bill Woodson – Narrator, Captain Croner (in "The Whirlpool"), Dr. Scat (in "The Brain Machine"), Police Chief (in "The Brain Machine"), Earthor #2 (in "Invasion of the Earthors"), Secret Four Member #2 (in "The Secret Four"), Hydronoid Ruler (in "Invasion of the Hydronoids"), Professor (in "Doctor Fright"), Boris (in "The Monster of Dr. Droid"), Professor Fairweather (in "The Invisible Menace"), Newton Domehead (in "The Collector"), Professor Dalton (in "Alaska Peril"), Professor Zarkoff (in "Forbidden Power"), Mutant (in "Forbidden Power"), Dr. Markham (in "The Man Beasts of Xra"), Jay's Pop (in "Runaways"), Cleazor (in "Will the World Collide?"), Professor Comstock (in "Time Rescue") ==Episodes==