- Lee Powell
- Lt. Tom Grayson
- Bruce Bennett
- Lt. Frank Corby
- Eleanor Stewart
- Janet Warfield
- Montagu Love
- Gen. White
- Hugh Sothern
- Prof. Warfield
- Sam Flint
- Colonel Grayson
- Perry Ivins
- Crenshaw
- Forrest Taylor
- Benson
- John Picorri
- Gould - The Lightning's Hunchbacked Assistant
- John Davidson
- Lin Wing
- Tom London
- Wilso - Henchman at Steel Works, on Gehorda Island
- Alan Gregg
- Marco - Henchman in Gray Shirt at Steel Works
- Allen Mathews
- Todd - Henchman at Base ZY, later on the Wing
- Frank Baker
- Marine Prosecutor-General
- Thomas Carr
- Dock Clerk
- Howard Chase
- Marine Commandant of Gehorda Island
- Ken Cooper
- Thug in Trees Outside Warfield House
- Jack Daley
- Police Inspector at Lin Wing's House
- George DeNormand
- Marine at Burton Street
- Eddie Foster
- Cave and Carbon-Monoxide Thug
- Jerry Frank
- Garage Henchman
- Sherry Hall
- Mr. Brown
- Ray Hansen
- Marine Smith
- Reed Howes
- Parker - Cave and Carbon Monoxide Hnchman
- Bruce Lane
- Marine Corporal
- Theodore Lorch
- Wing Henchman
- George Magrill
- Jameson
- Millard McGowan
- Fourth Garage Thug
- Monte Montague
- Jacobs - Thug Spying at Warfield House, later Phoney Chauffeur
- Jack O'Shea
- Burly Garage Thug
- Henry Otho
- Sam Hedges
- Francis Sayles
- Renault
- William Stahl
- Marine Cpl. Lake
- Larry Steers
- Shanghai Base Marine Officer
- Harry Strang
- Marine Sgt. Bennett
- Al Taylor
- Carbon-Monoxide Thug
- Dirk Thane
- Thug on Shack Porch
- Robert J. Wilke
- Marine in Lu Kisan's Office
- Victor Wong
- Mikichan
- Joe Yrigoyen
- Marine in Lu Kisan's Office
