The People Against O'Hara

James P. Curtayne

Spencer Tracy

Det. Vincent Ricks

Pat O'Brien

Virginia 'Ginny' Curtayne

Diana Lynn

District Attorney Louis Barra

John Hodiak

Sol 'Knuckles' Lanzetta

Eduardo Ciannelli

John Fordman 'Johnny' O'Hara

James Arness

Mrs. Katrina Lanzetta

Yvette Duguay

Sven Norson

Jay C. Flippen

Frank Korvac

William Campbell

Jeff Chapman

Richard Anderson

Mr. O'Hara

Arthur Shields

Mrs. Peg O'Hara

Louise Lorimer

Judge Keating

Henry O'Neill

Betty Clark, Policewoman

Ann Doran

Captain Tom Mulvaney

Emile Meyer

Fred Colton, Police Sound Man

Regis Toomey

Mrs. William Sheffield (as Katharine Warren)

Katherine Warren

Waiter (uncredited)

John Albright

Little Wolfie (uncredited)

Tony Barr

Tony Korvac (uncredited)

Richard Bartlett

Gambler (uncredited)

Brooks Benedict

Harry (uncredited)

Leonard Bremen

Angelo Korvac (uncredited)

Charles Bronson

Receptionist (uncredited)

Mae Clarke

Vincent Korvac (as Lawrence Tolan) (uncredited)

Michael Tolan

James Korvac (uncredited)

Peter Mamakos

William Sheffield (uncredited)

Sailor Vincent

Preliminary Hearing Judge (uncredited)

Ned Glass

Pete Korvac (uncredited)

Bill Fletcher

Uniformed Detective (uncredited)

Jack Kruschen

Intern with Ambulance (uncredited)

William Schallert