But it will be a snow-free winter in Sheridan, Wyoming before you'll get Brannaman to accept that he's a movie star. When I finally track him down at his home in that town of 17,000 ("We don't have any real big towns out here," he says slowly), he tells me that the movie had to fit itself to him, not the other way around.
"When [director Cindy Meehl] came to me with the idea of this project, I said you're going to have a challenge. I worked on The Horse Whisperer all those years ago and they would set up the cameras and then tell the actors where to stand and what to do and they would shoot 'em doing it. And then they'd do it again.
"I said to Cindy, 'It's not going to work that way with this documentary. You're going to have to anticipate when something interesting is going to happen between me and someone else and a horse because I'm not going to stage anything or do anything over.
"If I say something that you really want to have on film, you better have gotten it the first time -'cos I ain't saying it again'."
On paper, it looks arrogant and forbidding but when Brannaman says it, it sounds like he's saying there'll be snow tonight: it's just how it is and it's no use pretending otherwise.
The film starts out looking like nothing more than a portrait of the artist, a man who spends 10 months a year on the road, driving a rig that looks like cross between an SUV and a horse-float and holding clinics for horse-owners and ranchers.
And if it never became anything else, Buck would be deeply satisfying. Brannaman's in his element at work, passing on the stuff he learnt from mentors Ray Hunt and Tom Dorrance, whose philosophy is distilled into the observation "if you get bucked off or kicked or bitten, you obviously did something wrong, and that's just too bad. The horse, on the other hand, is never, ever wrong".
But quickly we learn that we are seeing a man with a big back-story: a childhood of abuse by an cruel and obsessive father.
Far from destroying him, it gave him the empathy he needed to excel at what he does now - working with damaged animals, equine and human.
"I ain't helping people with horse problems," he says at one point during the film. "I'm helping horses with people problems." And, to a client: "This horse tells me a lot about you. Why don't you learn to enjoy your life?"
It's that aspect that strikes a chord with audiences, even those entirely uninterested in horses, says Brannaman. "I didn't want Cindy to do a documentary that appealed to horse people.
"It needed to appeal to someone who may never own a horse but is part of the human race like the rest of us and she accomplished that and that was no easy thing to do."
Meehl - a graduate of one of Brannaman's clinics who became a film-maker in order to tell his story - also managed show her subject without making him into a hero.
As a result, audiences are not standoffish around Brannaman at screenings he attends.
"People come up to me and tell stories of their own," he says with evident pleasure.
"I wanted the film to be encouraging to people who may be living in a dark time right now, so that they can understand that there can be a happy ending to things, depending on the choices that they make."
Lowdown
Who: Buck Brannaman
What: The documentary Buck
When: Opens Thursday
Also: Brannaman is in New Zealand at the moment conducting horsemanship clinics. His next is at Taupo's National Equestrian Centre Jan 21-23. Go to www.horsemanshipnz.com
-TimeOut
