 Spencer TracyJames P. Curtayne | James P. Curtayne |
 Pat O'BrienDet. Vincent Ricks | Det. Vincent Ricks |
 Diana LynnVirginia 'Ginny' Curtayne | Virginia 'Ginny' Curtayne |
 John HodiakDistrict Attorney Louis Barra | District Attorney Louis Barra |
 Eduardo CiannelliSol 'Knuckles' Lanzetta | Sol 'Knuckles' Lanzetta |
 James ArnessJohn Fordman 'Johnny' O'Hara | John Fordman 'Johnny' O'Hara |
 Yvette DuguayMrs. Katrina Lanzetta | Mrs. Katrina Lanzetta |
 Jay C. FlippenSven Norson | Sven Norson |
 William CampbellFrank Korvac | Frank Korvac |
 Richard AndersonJeff Chapman | Jeff Chapman |
 Arthur ShieldsMr. O'Hara | Mr. O'Hara |
 Louise LorimerMrs. Peg O'Hara | Mrs. Peg O'Hara |
 Henry O'NeillJudge Keating | Judge Keating |
 Ann DoranBetty Clark, Policewoman | Betty Clark, Policewoman |
 Emile MeyerCaptain Tom Mulvaney | Captain Tom Mulvaney |
 Regis ToomeyFred Colton, Police Sound Man | Fred Colton, Police Sound Man |
 Katherine WarrenMrs. William Sheffield (as Katharine Warren) | Mrs. William Sheffield (as Katharine Warren) |
| JJohn AlbrightWaiter (uncredited) | Waiter (uncredited) |
| TTony BarrLittle Wolfie (uncredited) | Little Wolfie (uncredited) |
| RRichard BartlettTony Korvac (uncredited) | Tony Korvac (uncredited) |
 Brooks BenedictGambler (uncredited) | Gambler (uncredited) |
 Leonard BremenHarry (uncredited) | Harry (uncredited) |
 Charles BronsonAngelo Korvac (uncredited) | Angelo Korvac (uncredited) |
 Mae ClarkeReceptionist (uncredited) | Receptionist (uncredited) |
 Michael TolanVincent Korvac (as Lawrence Tolan) (uncredited) | Vincent Korvac (as Lawrence Tolan) (uncredited) |
 Peter MamakosJames Korvac (uncredited) | James Korvac (uncredited) |
 Sailor VincentWilliam Sheffield (uncredited) | William Sheffield (uncredited) |
 Ned GlassPreliminary Hearing Judge (uncredited) | Preliminary Hearing Judge (uncredited) |
| BBill FletcherPete Korvac (uncredited) | Pete Korvac (uncredited) |
 Jack KruschenUniformed Detective (uncredited) | Uniformed Detective (uncredited) |
