Billy Crudup
as Dr. Philip Zimbardo

Michael Angarano
as Christopher Archer

Ezra Miller
as Daniel Culp / Prisoner 8612

Tye Sheridan
as Peter Mitchell / Prisoner 819

Olivia Thirlby
as Dr. Christina Maslach

Nelsan Ellis
as Jesse Fletcher

Moisés Arias
as Anthony Carroll

Nicholas Braun
as Karl Vandy

Gaius Charles
as Paul Vogel

Keir Gilchrist
as John Lovett

Ki Hong Lee
as Gavin Lee / Prisoner 3401

Thomas Mann
as Prisoner 416

Logan Miller
as Jerry Sherman / Prisoner 5486

Johnny Simmons
as Jeff Jansen / Prisoner 1037

James Wolk
as Mike Penny

Matt Bennett
as Kyle Parker

Jesse Carere
as Paul Beattie / Prisoner 5704

Brett Davern
as Hubbie Whitlow / Prisoner 7258

James Frecheville
as Matthew Townshend

Miles Heizer
as Marshall Lovett

Jack Kilmer
as Jim Randall / Prisoner 4325

Callan McAuliffe
as Henry Ward

Benedict Samuel
as Jacob Harding

Chris Sheffield
as Tom Thompson / Prisoner 2093

Harrison Thomas
as Andrew Ceros

Albert Malafronte
as Father MacAllister

Danielle Lauder
as Mary Ann

Jim Klock
as Warren

Kate Butler
as Mrs. Mitchell

James C. Victor
as Mr. Mitchell

Fred Ochs
as Professor Jim Cook