Lon Chaney Jr. as Dan McCormick

Lionel Atwill as Dr. Paul Rigas

Anne Nagel as June Lawrence

Frank Albertson as Mark Adams

Samuel S. Hinds as Dr. John Lawrence

William B. Davidson as District Attorney Ralph B. Stanley

Ben Taggart as Detective Sergeant Regan

Constance Bergen as Nurse

Ivan Miller as Doctor

Chester Gan as Chinese Boy, Wong

George Meader as Dr. Bruno

Frank O'Connor as Detective

John Dilson as Medical Examiner

Byron Foulger as Alienist #2

Jessie Arnold as Mrs. Frank Davis (uncredited)

James Blaine as Charlie, Prison Guard (uncredited)

Gary Breckner as Radio Announcer (uncredited)

Lowell Drew as Jury Foreman (uncredited)

John Ellis as Assistant District Attorney (uncredited)

Douglas Evans as Police Radio Announcer (uncredited)

Jack Gardner as Reporter (uncredited)

William Hall as Mike - Dynamo Operator (uncredited)

Russell Hicks as Warden Harris (uncredited)

Wright Kramer as Judge (uncredited)

Tom Quinn as Detective (uncredited)

Bob Reeves as Prison Guard (uncredited)

Mel Ruick as Defense Attorney (uncredited)

Francis Sayles as Frank Davis (uncredited)

Paul Scott as Prison Chaplain (uncredited)

David Sharpe as Hay Wagon Passenger (uncredited)

Victor Zimmerman as Dynamo Operator #2 (uncredited)

Corky as Corky the Dog (uncredited)