- Jason Clarke - Roger Robb
- Dylan Arnold - Frank Oppenheimer
- Tom Conti - Albert Einstein
- James D'Arcy - Patrick Blackett
- David Dastmalchian - William Borden
- Dane DeHaan - Kenneth Nichols
- Alden Ehrenreich - Senate Aide
- Tony Goldwyn - Gordon Gray
- Jefferson Hall - Haakon Chevalier
- David Krumholtz - Isidor Rabi
- Matthew Modine - Vannevar Bush
- Scott Grimes - Counsel
- John Gowans - Ward Evans
- Macon Blair - Lloyd Garrison
- Harry Groener - Senator McGee
- Gregory Jbara - Chairman Magnuson
- Ted King - Senator Bartlett
- Tim DeKay - Senator Pastore
- Steven Houska - Senator Scott
- Petrie Willink - Dutch Student
- Matthias Schweighöfer - Werner Heisenberg
- Alex Wolff - Luis Alvarez
- Josh Zuckerman - Rossi Lomanitz
- Rory Keane - Hartland Snyder
- Michael Angarano - Robert Serber
- Emma Dumont - Jackie Oppenheimer
- Sadie Stratton - Mary Washburn
- Guy Burnet - George Eltenton
- Tom Jenkins - Richard Tolman
- Louise Lombard - Ruth Tolman
- Michael Andrew Baker - Joe Volpe
- Jeff Hephner - Congressman
- Olli Haaskivi - Edward Condon
- David Rysdahl - Donald Hornig
- Josh Peck - Kenneth Bainbridge
- Jack Quaid - Richard Feynman
- Brett DelBuono - Concerned Scientist
- Gustaf Skarsgård - Hans Bethe
- James Urbaniak - Kurt Gödel
- Trond Fausa Aurvåg - George Kistiakowsky
- Devon Bostick - Seth Neddermeyer
- Danny Deferrari - Enrico Fermi
- Christopher Denham - Klaus Fuchs
- Jessica Erin Martin - Charlotte Serber
- Máté Haumann - Leo Szilard
- Olivia Thirlby - Lilli Hornig
- Jack Cutmore-Scott - Lyall Johnson
- Harrison Gilbertson - Philip Morrison
- James Remar - Henry Stimson
- Will Roberts - George C. Marshall
- Pat Skipper - James Byrnes
- Steve Coulter - James Conant
- Jeremy John Wells - AAF Officer
- Sean Avery - Weatherman
- Drew Kenney - Soldier
- Bryce Johnson - AAF Officer 2
- Flora Nolan - Burn Victim
- Kerry Westcott - Laughing Woman
- Christina Hogue - Kissing Woman
- Clay Bunker - Kissing Man
- Kate French - Presidential Aide
- Gary Oldman - Harry Truman
- Hap Lawrence - Lyndon Johnson
- Meg Schimelpfenig - Senator's Assistant (uncredited)
- Samarth Ror - Samarth Oppenheimer
- Andrew Stahl
- Nilo Otero
- Richard Molloy
- Steve Gehrke
- Kai Bird
- Christopher Nolan
- Martin J. Sherwin
- Charles Roven
- Emma Thomas
- John Papsidera
- Nathan Kelly
- James Woods
- Dan O'Connell
- Gary Rizzo
- Douglas Shamburger
- Ludwig Göransson
Capítulo disponible en las siguientes plataformas:
