- Pat O'Brien
- Chief Michael 'Mike' Mallory
- George Murphy
- Lt. Thomas L. 'Tom' Sands
- Jane Wyatt
- Myra Mallory
- Jackie Cooper
- Joe 'Babe' Duttson
- Carl Esmond
- Richard 'Dutch' Kroner
- Max Baer
- Coxswain G. Berringer
- Desi Arnaz
- Pat Tarriba
- Ray Collins
- Capt. McCall
- Lee Bonnell
- Kovac
- Frank Jenks
- Sampier
- John McGuire
- James Bayless
- Frank Fenton
- Hodum
- Joey Ray
- James Dennis
- Marten Lamont
- Lt. Cmdr. Murray - navy doctor
- Stanley Andrews
- Judge Advocate
- George Blagoi
- U-Boat Captain
- Sven Hugo Borg
- U-Boat First Officer
- Egon Brecher
- U-Boat Commander
- Joe Cunningham
- Mr. Duttson
- Helmut Dantine
- Frightened Young German Seaman
- Edgar Dearing
- Bud
- Ralph Dunn
- Cop Bringing Sampier
- Bud Geary
- Quartermaster McPhail
- Joseph W. Girard
- Naval Captain at Hearing
- William Haade
- Pier 7 Guard
- Russell Hoyt
- Minor Role
- Mike Lally
- Merchant Marine Sailor with Hose
- Howard Lane
- Lookout
- Lyle Latell
- Oiler
- Jack Martin
- U-Boat First Officer
- George Melford
- Chief Engineer
- Monte Montague
- Third Mate
- William H. O'Brien
- Clerk at Hearing
- Cyril Ring
- Mr. Reynolds
- Franklin D. Roosevelt
- Self
- Hans Schumm
- U-51 Captain Recognizing Kroner
- Robert R. Stephenson
- First Officer of 'Odin'
- Fred Sweeney
- Lookout
- Sigfrid Tor
- German First Officer
- Nicholas Vehr
- U-Boat First Officer
- Wilhelm von Brincken
- Captain of 'Odin'
- Hans Heinrich von Twardowski
- U-Boat Captain
- Malcolm Waite
- Top Lookout
- Max Waizmann
- German Agent
- Mary Young
- Mrs. Duttson
