Klaatu / Mr. Carpenter

Michael Rennie

Helen Benson

Patricia Neal

Tom Stevens

Hugh Marlowe

Bobby Benson

Billy Gray

Prof. Jacob Barnhardt

Sam Jaffe

Mrs. Barley

Frances Bavier

Gort

Lock Martin

General Cutler

Freeman Lusk

Mrs. Crockett

Edith Evanson

Drew Pearson

Drew Pearson

Harley

Frank Conroy

Colonel in Jeep

Carleton Young

Major General

Fay Roope

George Barley (boarder)

John Brown

Mr. Krull

Olan Soule

Hilda

Marjorie Crossland

Major White

Robert Osterloh

Elmer Davis

Elmer Davis

Brady

Tyler McVey

Government Man

James Seay

H. V. Kaltenborn

H.V. Kaltenborn

Interviewer

Glenn Hardy

Gabriel Heatter (voice)

Gabriel Heatter

Military Police Captain

House Peters Jr.

Lieutenant in Charge of Landing Site

Harry Lauter

Army Dr. White

James Doyle

Balding Army Doctor

Larry Dobkin

MP Sergeant

Rush Williams

Government Agent

Gil Herman

Businessman

James Craven

Conference Colonel Ryder

George Lynn

Major General

Charles Evans

Margaret

Dorothy Neumann

Mr. Carlson

Harlan Warde

Mr. Bleeker

Wheaton Chambers

Customer

Elizabeth Flournoy

The Cab Driver

Harry Harvey

Sammy

Sammy Ogg

Lady Outside Jewelry Store

Bess Flowers

British Radio MC

John Burton

Newscaster

George Reeves

Radar Operator

Grady Galloway

Indian Newscaster

Hassan Khayyam

Commentator

Gabriel Heater

British Newscaster

John Barton

Sentry (scene deleted)

Stuart Whitman

Scientific Delegate

Rama Bai

Radio Announcer (voice)

Bill Welsh

Newscaster

Marshall Bradford

Radio Operator (uncredited)

Guy Williams