 | Steve Carell als John du Pont |
 | Channing Tatum als Mark Schultz |
 | Mark Ruffalo als David Schultz |
 | Sienna Miller als Nancy Schultz |
 | Vanessa Redgrave als Jean du Pont |
 | Anthony Michael Hall als Jack |
 | Guy Boyd als Henry Beck |
 | Brett Rice als Fred Cole |
 | Jackson Frazer als Alexander Schultz |
 | Samara Lee als Danielle Schultz |
 | Francis J. Murphy III als Wayne Kendall |
| Jane Mowder als Rosie |
| David Bennett als Documentary Director |
 | Lee Perkins als Corporal |
| Robert Haramia als Banquet Guest |
 | Daniel Hilt als Roberto Garcia |
| Bryan Cook als Ben Langer |
| David Zabriskie als Dan Bane |
| Zach Rey als Foxcatcher Wrestler #1 |
| Reece Humphrey als Foxcatcher Wrestler #2 |
| J.D. Bergman als Foxcatcher Wrestler #3 |
| Corey Jantzen als Foxcatcher Wrestler #4 |
| Frederick Feeney als Seoul Referee |
 | Mark Schultz als Weigh-in Official #1 |
| Lee Kemp als Weigh-in Official #2 |
| Jake Herbert als Mark's Opponent at Trials |
| Donald Modrick als Front Gate Guard |
| Gabrielle Burton als School Secretary |
| Kevin Cooke als Photographer |
| Richard E. Chapla Jr. als Broiler Hut Cashier |
| Bill Ehrin als Broiler Hut Patron |
| Roger Callard als Helicopter Pilot |
| Dan Anders als General |
| Barry Vlanich als D.C. Partygoer |
| Sam Brehm als Hank Church |
| Stan Dziedzic als USA Wrestling Rep #1 |
| David Miller als USA Wrestling Rep #2 |
 | Brian Baumgartner als USA Wrestling Rep #3 |
| Joe Russo als Olympic Trials Referee |
| Ken Williams als Coach Ken |
| Gene Mills als Worlds Referee |
| John C. Baxter als Worlds Announcer |
| Rick Steigerwald als Wexler Trainer |
| Marc Snider als MMA Referee |
| Jaz Securo als MMA Announcer |
| Corey Walker als MMA Backstage Official |
 | Alan Oppenheimer als Du Pont Dynasty Narrator (voice) |
 | Joe Fishel als Trainer |
| Jackson Nunn als Spectator (uncredited) |
| Bennett Miller | Director |
| E. Max Frye | Writer |
| Dan Futterman | Writer |
| Stuart Levy | Editor |
| Greig Fraser | Director of Photography |
| Bennett Miller | Producer |
| Megan Ellison | Producer |
| Conor O'Neill | Editor |
| Jess Gonchor | Production Design |
| Kathy Lucas | Set Decoration |
| Jon Kilik | Producer |
| Anthony Bregman | Producer |
| Kasia Walicka Maimone | Costume Design |
| Bill Corso | Makeup Department Head |
| Jeanne McCarthy | Casting |
| Jay Cassidy | Editor |
| Tracy Scott | Script Supervisor |
| Scott Garfield | Still Photographer |
| Susan Jacobs | Music Supervisor |
| Darcie Buterbaugh | Costume Supervisor |
| Brad Ricker | Art Direction |
| Jenn Albaugh | Art Department Coordinator |
| Bela Trutz | Steadicam Operator |
| Bela Trutz | Camera Operator |
| Peter Bucossi | Stunt Coordinator |
| Jim Emswiller | Sound Mixer |
| Kathrine Gordon | Hair Department Head |
| Diane Dixon | Hair Department Head |
| Dennis Liddiard | Key Makeup Artist |
| Betty Lou Skinner | Key Hair Stylist |
| Michael Dolhi | Greensman |
| Kate Dougherty | Set Designer |
| Mike Matesic | Construction Foreman |
| Buster Pile | Construction Coordinator |
| Chad Birmingham | Foley Editor |
| Cameron Frankley | Sound Effects Editor |
| Paul Hsu | Supervising Sound Editor |
| Jac Rubenstein | ADR Editor |
| Allan Zaleski | Sound Effects Editor |
| Andrea Atwater | Visual Effects Coordinator |
| Jake Braver | Visual Effects Supervisor |
| Pinar Comezoglu | Visual Effects Editor |
| Naz Shams | Visual Effects Coordinator |
| Jesse Jantzen | Fight Choreographer |
| Dante Ludovici | Camera Operator |
| Brian S. Osmond | Camera Operator |
| Edward T. Hanley | Key Costumer |
| Peter Oso Snell | Supervising Music Editor |
| Branka Mrkic | Dialogue Editor |
| Jac Rubenstein | Dialogue Editor |
| Lawrence Zipf | Sound Recordist |
| Chelsea Barnard | Executive Producer |
| Ron Schmidt | Executive Producer |
| Mark Bakshi | Executive Producer |
| Michael Coleman | Executive Producer |
| Tom Heller | Executive Producer |
| John P. Giura | Executive Producer |
| Scott Robertson | Co-Producer |
| Rob Simonsen | Original Music Composer |
| West Dylan Thordson | Additional Music |
| Mark Schultz | Associate Producer |
| Kristin Gore | Associate Producer |
| Hank Bedford | Associate Producer |
| Ron Schmidt | Unit Production Manager |
| Scott Robertson | First Assistant Director |
| Jonas Spaccarotelli | Second Assistant Director |
| Tom Fleischman | Sound Re-Recording Mixer |
| Brice Liesveld | Visual Effects Producer |
| Arvo Pärt | Additional Soundtrack |
