Robert Redford bought the horse, Rising Star, after production was complete and owned him for 18 years before the horse died.
Director Sydney Pollack is also the voice of Les, Hallie Martin's boss, on the phone when she calls from the coffee shop to say that she's interviewed Sonny Steele.
Robert Redford did all of his own riding stunts in the film.
This movie was inspired by a case where "The Sonny and Cher Comedy Hour" (1971) invited Penny Chenery in 1973 to bring her horse, the legendary Triple Crown winner Secretariat to appear on the show. Chenery, knowing her horse wouldn't care for a TV studio, declined.
Sonny Steele signs the divorce papers right-handed. However, Robert Redford is famously left-handed.
When Gus responds to Hallie Martin's query about Sonny's whereabouts, the lines "like a flutterin' bird... like a mist... and blocks out the sun" are actually taken from Ovid's Metamorphoses: they are spoken by the Dawn, who laments her son's death on the plains of Troy.