(at around 37 mins) The part where Snyder rejects Billie's drink by pouring it over her hand was actually an accident. Charles Durning was supposed to pour the drink on the floor but Eileen Brennan's hand got in the way. They kept in character and she improvised the annoyed look and shaking off her hand at him.
Paul Newman and Robert Redford were each paid $500,000 for their role, the highest rate for an actor working at that time. Adjusted for inflation, that is equal to $3,713,000 (2025). The year before this Marlon Brando earned $3 million from Último tango en París (1972) but that included profit participation.
George Roy Hill used some 1930s stylistic techniques. The film starts with a 1930s-era Universal logo, and used editing wipes to transition between scenes and iris shots.
Edith Head won her 8th (and final) Best Costume Design Academy Award for this film. "Just imagine," she said during her acceptance speech, "dressing the two handsomest men in the world and then getting this."
Robert Shaw injured his knee and incorporated the resulting limp into his performance. According to "You'll Never Eat Lunch in This Town Again" by Julia Phillips, Shaw split all the ligaments in his knee after slipping on a wet handball court at the Beverly Hills Hotel a week before filming started. He had to wear a leg brace during production which was kept hidden under the wide 1930s style trousers he wore.