- Lee Powell
- Lt. Tom Grayson
- Bruce Bennett
- Lt. Frank Corley
- Eleanor Stewart
- Janet Warfield
- Montagu Love
- Col. White
- Hugh Sothern
- Ben Warfield
- Sam Flint
- Col. Grayson
- Perry Ivins
- Crenshaw, the lab assistant
- Forrest Taylor
- Benson, the butler
- John Picorri
- Prof. Gould
- Carleton Young
- Johnson, Aurora crewman
- John Davidson
- Lin Wing
- Henry Otho
- Sam, the gardener
- Reed Howes
- Parker, submarine crewman
- Tom London
- Wilson, a thug
- Edmund Cobb
- Ellis, a thug
- Alan Gregg
- Macro, a thug
- Allen Mathews
- Todd, submarine captain
- Edward Argyle
- Warehouse Five Watchman
- Frank Baker
- Court Martial General
- Ken Cooper
- Thug in Lake
- Jack Daley
- Police Inspector
- Eddie Foster
- Pete - Sub Thug
- Jerry Frank
- Thug at Garage and Kidnapping
- Sherry Hall
- Mr. Brown
- Theodore Lorch
- Captain of 'The Wing'
- George Magrill
- Jamison - Chauffeur
- Millard McGowan
- Thug in White Suit
- Monte Montague
- Jacobs - Thug
- Jack O'Shea
- Thug at Garage and Gateway
- Francis Sayles
- Renault - Lab Aide
- William Stahl
- Cpl. Lake
- Larry Steers
- Capt. King
- Harry Strang
- Sgt. Bennett
- Al Taylor
- Submarine Thug
- Dirk Thane
- Tall Thug
- Duke York
- Sam - Thug on Yacht
