- Billy Halop
- Billy Barton
- Huntz Hall
- Gyp
- Gabriel Dell
- Terry
- Bernard Punsly
- Lug
- Ken Lundy
- Buck
- Kenneth Howell
- Harry Trent
- Roger Daniel
- Midge
- Phillip Terry
- Jim Bradford
- Russell Hicks
- Col. Barton
- Cy Kendall
- Brand
- Ben Taggart
- Severn
- Victor Zimmerman
- Corey
- Edgar Edwards
- Evans
- Gene Rizzi
- Foster
- Florence Halop
- Mary
- Harris Berger
- Sailor
- Jean Brooks
- Waitress [Chs. 11-12]
- Bill Cartledge
- Junior G-Man [Chs. 1, 6]
- Lane Chandler
- Second Cop at Building Collapse [Ch. 6]
- Jack Cheatham
- First Cop at Building Collapse [Ch. 6]
- Hal E. Chester
- Murph
- Donald Curtis
- Henchman Akin
- William Desmond
- Irish Cop [Ch. 6]
- Ray Dixon
- Audience Member at Boxing Match
- Julie Duncan
- Crawford's Secretary
- George Eldredge
- Draftsman Lynch [Chs. 5-6]
- Jim Farley
- Accusing Pedestrian [Ch. 1]
- Edward Fielding
- Professor Farraday [Chs. 9-10]
- William Hall
- FBI Agent Watson [Ch. 11]
- Kenneth Harlan
- Dyer, Factory Gate Guard [Ch. 9]
- Lew Harvey
- Woods - Farraday's Pilot [Ch. 9]
- Al Hill
- Burke, Second Henchman
- Ethan Laidlaw
- Watchman [Chs. 5-6]
- Tom London
- Kearney - Riot Squad Cop [Ch. 1]
- Pierce Lyden
- Henchman
- Charles McAvoy
- Policeman [Ch. 9]
- Robert McKenzie
- Undetermined Secondary Role
- Charles McMurphy
- Police Officer Foley [Ch. 10]
- Bert Moorhouse
- Elevator Operator [Ch. 1]
- Eddie Parker
- Truck Driver [Ch. 1]
- Ralph Peters
- Flaming Torch Member
- Jack Roper
- Slugger - the Pug [Ch. 1]
- Dick Rush
- Policeman Mike [Ch. 1]
- David Sharpe
- Henchman on Stairs [Ch. 10]
- Tom Steele
- Bakery Truck Driver [Ch. 1] / Police Driver [Ch. 4] (uncredited)
- Ray Turner
- Chauffeur [Ch. 1]
