Clifton Collins Jr. has made a career out of being a supporting player. Even if the average moviegoer might not know his name, you know his face and his work. Collins always manages to stand out, whether in a pivotal role like Perry Ellis in “Capote” or a glorified cameo in “Once Upon a Time in Hollywood.” He’s got acting in his blood: His grandfather was character actor Pedro Gonzalez Gonzalez who appeared in a number of John Wayne films, including “Rio Bravo,” and his great uncle was a Hollywood player too.

It was probably inevitable that Collins would eventually find himself on a horse in a Western, not counting the blink and you’ll miss him moment in Quentin Tarantino’s fake show-within-a-show. And he couldn’t have picked a better showcase for his own talents and legacy than “Jockey,” a quiet, moving indie about a champion rider grappling with the end of his own run.

“Jockey” is the directorial debut of Clint Bentley, who basically grew up on the racetrack alongside his jockey father. He wanted to show the jockey lifestyle as it really is, which he felt was lacking in films about the grueling profession. That might be a little debatable, and it’s not dissimilar in tone and ambition to Chloé Zhao’s rodeo film “The Rider.” But Collins is there to give a full body performance as Jackson Silva, a legend in his time who has suffered a few too many broken backs along the way and might need to hang up his spurs sooner than he’d like.

Intensifying this already fraught moment is the arrival of two complications: A 19-year-old kid with jockey dreams, Gabriel (Moises Arias), who claims he’s Jackson’s son, and a once-in-a-lifetime champion horse that Jackson is not going to pass off to some young buck for the big race. Molly Parker plays his boss, Ruth, who wants to give Jackson another shot, but can see the toll the years and riding

Bentley clearly has a love for this peculiar lifestyle, in which already rail thin men are forever striving to lose another pound or two and whose bodies are ravaged by the sport. He shows the track (a real, working racetrack) and the riders beautifully, if a little romantically. It always seems to be magic hour when cinematographer Adolpho Veloso’s cameras are rolling, and all the characters get a wistful monologue or folksy truism to spout out while the colorful sky turns to night.

Realism might have been the goal, but Bentley employs a very familiar indie film framework to tell the story that could be best summed up as Sundance-verité, right down to its cool score by none other than Aaron and Bryce Dessner of The National. That’s not a bad thing — it’s a time-tested style for a reason — but this isn’t exactly a film that’s full of surprises.

And yet the framework, as predictable as it is, works because of the sincerity behind the endeavor and the depth of Collins’ performance. He is the heart and soul of “Jockey,” and no one who gives it a chance will be forgetting his name anytime soon.

“Jockey,” a Sony Pictures Classics release now playing in New York and Los Angeles, is rated R by the Motion Picture Association of America for “language.” Running time: 95 minutes. Two and a half stars out of four.