Olympic wrestling champion Mark Schultz (Channing Tatum) finds himself in an unexpected situation when he speaks at an elementary school on behalf of his older brother, Dave Schultz (Mark Ruffalo). Although both are gold medal-winning wrestlers, Mark often feels overshadowed by his sibling's accomplishments. His life takes a turn when he meets John E. Du Pont (Steve Carell), a wealthy philanthropist and wrestling enthusiast from the famous Du Pont family. Du Pont invites Mark to his Pennsylvania estate, where he has established a private wrestling training center. Enticed by the promise of financial support and the chance to be part of the "Team Foxcatcher" wrestling squad, Mark eagerly accepts, even trying to bring Dave along.
However, Dave prioritizes his family life and declines the offer, leaving Mark to move to Pennsylvania alone. He settles into a comforting guest house known as "the chalet," where he is soon visited by Du Pont. Under the mentor's financial guidance and the camaraderie of his teammates, Mark finds success with Team Foxcatcher, clinching a gold medal at the 1987 World Wrestling Championships with critical coaching from Dave. Their bond deepens, but as Du Pont introduces Mark to cocaine, he begins to struggle with his new lifestyle. In a moment of vulnerability, Du Pont reveals his mother, Jean Du Pont (Vanessa Redgrave), once paid a boy to be his friend, confiding that she considers wrestling a "low sport."
Tensions heighten when Mark and his teammates take time off from training to watch mixed martial arts (MMA) on television, which infuriates Du Pont. This incident ignites a series of confrontations, leading Du Pont to insist on enlisting Dave by any means necessary. Eventually, Dave relents and moves to Pennsylvania to join Team Foxcatcher, when Du Pont offers to compensate him generously. Meanwhile, Mark feels increasingly isolated and starts to distance himself from both Du Pont and Dave as he grapples with feelings of inadequacy.
As they prepare for the 1988 Summer Olympics in Seoul, Du Pont's erratic behavior escalates. He awkwardly demonstrates techniques to impress his mother during her visit to the training facility. After a disappointing performance at the Olympic Trials in Pensacola, Florida, Mark's emotional state deteriorates, leading him to destroy his room in a fit of rage. Driven by concern for his brother, Dave helps Mark regain his footing, leading to his final selection for the Olympic team.
Despite navigating the pressures surrounding him, Mark's Olympic experience is fraught with disappointment and he ultimately parts ways with Team Foxcatcher. Refusing to be part of Du Pont's toxic influence, Mark opts to leave, while Dave remains, negotiating arrangements to continue receiving Du Pont's support.
Tragedy strikes when Du Pont visits Dave at his home, where an unprovoked confrontation leads to Dave being shot at close range. As his wife Nancy (Sienna Miller) rushes outside in a frantic bid for help, she finds Dave dying in her arms. In the aftermath, Du Pont faces arrest, and the film culminates with a scene showing Mark competing in a cage fighting match, haunted by the cheers of the crowd.
In the years that ensued, Nancy and her children relocated to Northern California, while Mark transitioned away from competitive wrestling to become a coach and motivational speaker in Oregon. Following a multi-million dollar civil suit settlement, Du Pont endured a drawn-out legal battle where he was ultimately convicted but deemed mentally ill for Dave's murder. He received a substantial prison sentence and passed away in 2010 after spending nearly 15 years behind bars. The once-renowned Foxcatcher Farm has since been sold and transformed, with remnants of the estate now serving new purposes, marking the end of an era.
