Hugh Marlowe
Dr. Russell A. Marvin
Acting
Joan Taylor
Carol Marvin
Acting
Donald Curtis
Maj. Huglin
Acting
Morris Ankrum
Brig. Gen. John Hanley
Acting
Thomas Browne Henry
Vice Adm. Enright
Acting
Grandon Rhodes
Gen. Edmunds
Acting
John Zaremba
Prof. Kanter
Acting
Paul Frees
Alien (voice)
Acting
Frank Wilcox
Alfred Cassidy
Acting
Sydney Mason
Frank the garage man
Acting
Larry J. Blake
Motorcycle cop
Acting
Bert Stevens
Air Intelligence Command Officer
Acting
Forbes Murray
Military Officer at Experiment
Acting
Arthur Tovey
Officer/Civilian at Military Conference
Acting
Alan Wells
Major Kimberly
Acting
Nicky Blair
Military Officer at Experiment (uncredited)
Acting
Jimmy Cross
Military Messenger (uncredited)
Acting
Jack Deery
Military Officer (uncredited)
Acting
Charles Evans
Dr. Alberts (uncredited)
Acting
Raoul Freeman
Military Official (uncredited)
Acting
Paul Frees
Alien (voice) (uncredited)
Acting
James Gonzalez
Military Official (uncredited)
Acting
Duke Green
Minor Role (uncredited)
Acting
Ed Haskett
Military Official (uncredited)
Acting
Clark Howat
Sgt. Nash (uncredited)
Acting
Harry Lauter
Cutting - Generator Technician (uncredited)
Acting
Don Marlowe
Minor Role (uncredited)
Acting
William Meader
Worker in Control Tower (uncredited)
Acting
Sol Murgi
Plane Passenger (uncredited)
Acting
Forbes Murray
Military Officer at Experiment (uncredited)
Acting
William J. O'Brien
Radio Listener (archive footage) (uncredited)
Acting
Murray Pollack
Plane Passenger (uncredited)
Acting
Mike Ragan
Tank Commander (uncredited)
Acting
Alan Reynolds
Maj. Kimberly (uncredited)
Acting
Dale Van Sickel
Man Crushed Beneath Wall (uncredited)
Acting
Guy Way
Civilian Observing Saucer Attack (uncredited)
Acting
Bob Whitney
Plane Passenger (uncredited)
Acting
Frank Wilcox
Alfred Cassidy (uncredited)
Acting
Beal Wong
Chinese Radio Listener (uncredited)
Acting
William Woodson
Narrator (voice) (uncredited)
Acting