The People Against O'Hara

Spencer Tracy

James P. Curtayne

Pat O'Brien

Det. Vincent Ricks

Diana Lynn

Virginia 'Ginny' Curtayne

John Hodiak

District Attorney Louis Barra

Eduardo Ciannelli

Sol 'Knuckles' Lanzetta

James Arness

John Fordman 'Johnny' O'Hara

Yvette Duguay

Mrs. Katrina Lanzetta

Jay C. Flippen

Sven Norson

William Campbell

Frank Korvac

Richard Anderson

Jeff Chapman

Arthur Shields

Mr. O'Hara

Louise Lorimer

Mrs. Peg O'Hara

Henry O'Neill

Judge Keating

Ann Doran

Betty Clark, Policewoman

Emile Meyer

Captain Tom Mulvaney

Regis Toomey

Fred Colton, Police Sound Man

Katherine Warren

Mrs. William Sheffield (as Katharine Warren)

John Albright

Waiter (uncredited)

Tony Barr

Little Wolfie (uncredited)

Richard Bartlett

Tony Korvac (uncredited)