Michael Rennie

Klaatu / Mr. Carpenter

Patricia Neal

Helen Benson

Billy Gray

Bobby Benson

Sam Jaffe

Prof. Jacob Barnhardt

Hugh Marlowe

Tom Stevens

Lock Martin

Gort

Freeman Lusk

General Cutler

Edith Evanson

Mrs. Crockett (uncredited)

Frank Conroy

Mr. Harley

Frances Bavier

Mrs. Barley

John Brown

George Barley

Olan Soule

Mr. Krull

Marjorie Crossland

Hilda (uncredited)

Harry Lauter

Lieutenant in Charge of Landing Site

Robert Osterloh

Army Examining Doctor

Tyler McVey

Brady

House Peters Jr.

M.P. Captain at Barnhardt's

George Lynn

Conference Colonel Ryder

Dorothy Neumann

Margaret

Wheaton Chambers

Mr. Bleeker

Carleton Young

Zone Five Lieutenant Colonel

Harry Harvey

The Cab Driver

Bess Flowers

Lady Outside Jewelry Store

James Seay

Government Man (uncredited)

Stuart Whitman

Sentry (deleted scene)

Guy Williams

Radio Operator (uncredited)

Larry Arnold

Scientific Delegate (uncredited)

Patrick Aherne

General at Pentagon (uncredited)

Chet Brandenburg

Farmer (uncredited)

Marshall Bradford

Chief of Staff (uncredited)

Spencer Chan

Scientific Delegate (uncredited)

Eric Corrie

British Soldier (uncredited)

James Craven

Businessman (uncredited)

Lawrence Dobkin

Army Physician (uncredited)

Roy Engel

Government Man (uncredited)

Charles Evans

Major General (uncredited)

Franklyn Farnum

Extra in Office Building Corridor (uncredited)

James Gonzalez

Military Officer at Pentagon Meeting (uncredited)