Steve Carell claimed that, according to director Bennett Miller's wishes, there was no joking between takes, and he did not socialize with the co-stars after work.
Mark Ruffalo said the cast and crew were so afraid of Steve Carell as John du Pont that they tried to avoid interacting with him. Ruffalo said "Everyone sort of stayed away from him. John du Pont was repellent, so the way they designed Steve's look, it made him repellent, and you didn't know what to say to him or how to act around him. You never felt comfortable."
According to Channing Tatum, he and Mark Ruffalo spent an intensive five to six months training for wrestling, which took its toll on the actors. During one particularly physical take, Channing insisted to Ruffalo "just slap the shit out of me and get it over with", which resulted in Channing's eardrum accidentally getting popped. The take is in the film.
Before filming a particularly dark scene, Bennett Miller made Steve Carell write on a piece of paper the thing that he hates the most about himself and then put it in his pocket. Miller told Carell, "Just have it right there, and know that it's in a place where, if I was a dick, I could just grab it." According to Miller, the result is the favorite thing that he has put on film.
In the 1984 Olympic games, Dave Schultz and Mark Schultz were accused of "excessive brutality" in their Olympic matches, and a special official was assigned to monitor the rest of their bouts. Two of their opponents went straight to the hospital after their matches. Mark, 23, broke the left elbow of the 180.5-pound European champion Baris Karabacak thirty seconds into the match. Dave sent Yugoslavia's Saban Sejdi to the hospital with a knee injury incurred during their 163-pound match.
Mark Schultz: The real Mark can be seen as an extra weighing in wrestlers. This is amazing because Schultz hated the final product, particularly the scenes implying there was some sort of subtle, unrequited "bromance" between him and John du Pont. Schultz took to Twitter calling Bennett Miller, a "p---y and a liar". Later he apologized for his comments, walking them back, and saying Miller's movie is "an important movie" and is one of the "biggest things to happen for Olympic wrestling ever".