- Kirk Alyn
- Chris Calvert
- Jean Dean
- Joan Hughes
- Anthony Warde
- Ricco Morgan
- George J. Lewis
- Lt. Manuel Agura
- Eve Whitney
- Nitra
- John Merton
- John Baroda
- Tristram Coffin
- Franklyn Lord [Chs. 1, 10]
- John Crawford
- Sands [Chs. 7-8]
- Harold Goodwin
- Miller, Power Station Mgr. [Ch. 7]
- Dale Van Sickel
- Truck Driver Thomas [Ch. 3] / Henchman Lentz [Ch. 7]
- Tom Steele
- Henchman Ames [Chs. 1, 3, 10] / Henchman Gorman [Ch. 6]
- Eddie Parker
- Dutch [Chs. 1-4] / Herb [Chs. 5-6] / Malloy [Ch. 7] / Heavy Bender [Ch. 11] / Nash / White
- Forbes Murray
- Radar Committee Member 2 [Ch.12]
- Frank O'Connor
- Radar Committee Member 1 [Ch. 12]
- Stephen Gregory
- Hugo, Pilot [Chs. 1,5, 12]
- Frank Dae
- Senator John Clark [Ch. 12]
- Arvon Dale
- Roadblock Trooper [Ch. 8]
- Roy Barcroft
- Police Dispatcher [Ch. 3]
- John Daheim
- Henchman Jackson [Chs. 5, 9-10] / Henchman Hanley (uncredited)
- Art Dillard
- Henchman
- Charles Flynn
- Finney, Express Depot Clerk [Ch. 6]
- Bert LeBaron
- Nick, Power Unit Heavy [Ch. 11]
- Carey Loftin
- Cave Heavy [Ch. 9-10]
- David Sharpe
- Cliff, Laundry Heavy [Ch. 3]
- Duke Taylor
- Henchman Link [Chs. 2, 11]
- Ken Terrell
- Tami, the Mechanic [Chs. 2, 10]
- Bud Wolfe
- Kraft, Oil Company Office Henchman [Ch. 5]
