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 C. 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