
Leo Szilard flees Europe for the United States, where, aided by Einstein, he urges the government to develop an atomic bomb. General Leslie Groves is assigned the project and appoints J. Robert Oppenheimer to lead the Los Alamos Laboratory in New Mexico. As World War II ends, Szilard questions the weapon’s morality while officials debate when and if to use it.
Does Day One have end credit scenes?
No!
Day One does not have end credit scenes. You can leave when the credits roll.
Explore the complete cast of Day One, including both lead and supporting actors. Learn who plays each character, discover their past roles and achievements, and find out what makes this ensemble cast stand out in the world of film and television.

David Strathairn
J. Robert Oppenheimer

Brian Dennehy
Gen. Leslie Groves

Hume Cronyn
James F. Byrnes

Tony Shalhoub
Enrico Fermi

Barnard Hughes
Henry Stimson

Richard Dysart
President Harry S. Truman

Hal Holbrook
Gen. George Marshall

Lawrence Dane

David Ogden Stiers
Franklin D. Roosevelt

Olek Krupa
Edward Teller

George R. Robertson
Ed Condon

Timothy Webber
Colonel Lansdale

John McMartin
Dr. Arthur Compton

Michael J. Reynolds
Kenneth Bainbridge

Romano Orzari
Leo Szilard's Prime Scientist (uncredited)

Patrick Breen
Richard Feynman

Ron White
Colonel Nichols

Tom Butler
Captain DeSilva

Ken Pogue
Dwight D. Eisenhower

Scott Thomson
Chemist

Alan Scarfe

David Ferry
Army Major

Ron Frazier
Colonel Pash

Anne Twomey
Kitty Oppenheimer

David Gow
Jack Wisnovsky

Arthur Holden
Scientist (uncredited)

Vlasta Vrana
Hans Bethe

François Klanfer
Haagen Kistiakowski

Harry Strandjofski
Robert Wilson

Lorne Brass
Klaus Fuchs

Frederick Neumann
Alexander Sachs

Gary Reineke
Groves's Commanding Officer

Steve Barry
Los Alamo Scientist (uncredited)

Michael Farrell
Shapp

Graham Haley
Haakon Chevalier

Kliment Denchev
Michael Polanyi

Joel Miller
George Kistiakowski

Terrence Labrosse
Allan Dulles

John Pielmeier
Seth

Norris Domingue
General Pa Watson

Lia Sargent
Mrs. Wisnovsky

John Seitz
Ralph A. Bard

Philip Spensley
British Sr. Officer

Bob Clout
Alfred MacCormack

David Bolt
Harry Gold

Michael Sinelnikoff
Lord Rutherford

Roland Hewgill
Army General

Nicholas Kilbertus
Paul Tibbets

Robert Morelli
T. O. Jones

Peter Boretski
Albert Einstein

Dee McCafferty
William 'Deke' Parsons

Bernie McInerney

Isabelle Mejias
Mrs. Trowbridge

Jon Baggaley
James Tuck

Alex Guard
British Jr. Officer

Jonathan Wise
Robert Serber

Ester Spitz
Trude Weiss

Stephan Balint
Eugen Wigner

George Popovich
Samuel Goudsmit

Diana Fajrajsl
Ilse Polanyi

Heinar Pillar
Fleischmann

Ed McGibbon
William D. Leahy

Joe Cazalet
Air Force Guard

Stan Gibbons
John J. McCloy

Delise Alison
London Pedestrian
Discover where to watch Day One online, including streaming platforms, rental options, and official sources. Compare reviews, ratings, and in-depth movie information across sites like IMDb, TMDb, Rotten Tomatoes or Letterboxd.
It appears Day One does not have a summary available yet. Please consider requesting one.

Coming soon on iOS and Android
From blockbusters to hidden gems — dive into movie stories anytime, anywhere. Save your favorites, discover plots faster, and never miss a twist again.
Sign up to be the first to know when we launch. Your email stays private — always.
Immerse yourself in the magic of cinema with live orchestral performances of your favorite film scores. From sweeping Hollywood blockbusters and animated classics to epic fantasy soundtracks, our curated listings connect you to upcoming film music events worldwide.
Explore concert film screenings paired with full orchestra concerts, read detailed event information, and secure your tickets for unforgettable evenings celebrating legendary composers like John Williams, Hans Zimmer, and more.
Discover the central themes, ideas, and keywords that define the movie’s story, tone, and message. Analyze the film’s deeper meanings, genre influences, and recurring concepts.
Explore the various alternative titles, translations, and other names used for Day One across different regions and languages. Understand how the film is marketed and recognized worldwide.
Browse a curated list of movies similar in genre, tone, characters, or story structure. Discover new titles like the one you're watching, perfect for fans of related plots, vibes, or cinematic styles.
What's After the Movie?
Not sure whether to stay after the credits? Find out!
Explore Our Movie Platform
New Movie Releases (2026)
Famous Movie Actors
Top Film Production Studios
Movie Plot Summaries & Endings
Major Movie Awards & Winners
Best Concert Films & Music Documentaries
Movie Collections and Curated Lists
© 2026 What's After the Movie. All rights reserved.