Voice of the Whistler

Richard Dix

as John Sinclair / John Carter

Lynn Merrick

as Joan Martin Sinclair

Rhys Williams

as Ernie Sparrow

James Cardwell

as Fred (Doc) Graham

Tom Kennedy

as Ferdinand / Hammerlock

Sam Ash

as Gibson Motor Car Co. Executive (uncredited)

Egon Brecher

as Dr. Rose (replaced by Frank Reicher) (uncredited)

Charles Coleman

as Sinclair's Butler (uncredited)

Otto Forrest

as The Whistler (uncredited)

Byron Foulger

as Georgie (uncredited)

Martín Garralaga

as Tony, Fruit Peddler (uncredited)

John Hamilton

as Doctor (uncredited)

Stuart Holmes

as Sinclair Executive (uncredited)

Wilbur Mack

as Sinclair Executive (uncredited)

Charles Marsh

as Sinclair Executive (uncredited)

Harold Miller

as Sinclair Executive (uncredited)

Forbes Murray

as Sinclair Executive (uncredited)

Gigi Perreau

as Bobbie (uncredited)

Frank Reicher

as Dr. Rose (uncredited)

Clinton Rosemond

as Train Porter (uncredited)

Frank J. Scannell

as Druggist (uncredited)

Minerva Urecal

as Georgie's Wife (uncredited)

Robert B. Williams

as Pharmacist (uncredited)

Douglas Wood

as Paul Kitridge - Attorney (uncredited)