Peter Breck

as Hull

as Ward Bannister

as Silver Cloud

as Farmer Brown (voice)

as Harry Cordel

as Johnny Barrett

as Kendal's Father

as Dr. Paul M. Chapman

as Senator Orville

as King Leonidas

as Clay Elliot

as Ben Miranda (uncredited)

as Fly Hoyt

as Stacey Gouge (uncredited)

as Nick Barkley

as Sheriff Hatch

as Tibor

as Jess Carver

as Steve Curan

as George Noland

as Mr. Watson

as Chip

as Bob Mooney

as Chambers

as Sahm-Ir

as Dr. Halverson

as Sam Dixon

as Sundance Kid

as Wellington

as Lt. John Stickney

as Mike Palmer

as Theodore Roosevelt

as Russian Officer

as Johnny Barrett (archive footage) (uncredited)

as Ross Gilmore

as Clay Culhane

as Wiley Bondesen

as Stephen Tremayne

as Dr. Ted Dietrich

as Avery Porter

as Ted Grover

as Senator Weyburn

as Frank Brennan