This sounds like a very engaging documentary about George Plimpton. There was a time he was a celebrity, famous for Paper Lion, his account of his tryout with the Detroit Lions in the 1960s. It seems Plimpton prefigured the celebrity reality show, so common today. He was also an excellent sportswriter, covering Ali's grand comeback in his victory of George Foreman in Kinshasha, Zaire, otherwise known as "The Rumble in the Jungle."
His greatest legacy is The Paris Review, which he co-founded with Harold Humes and Peter Mathiesen, putting him in contact with virtually all the leading lights of literature, including Ernest Hemingway, who he apparently rubbed the wrong way when he asked him about the white birds popping up in Hemingway's sex scenes.
George Plimpton generally tended to play himself in film, but he popped up in a few movies as other characters, including the psychologist, Henry Lipkin, in Good Will Hunting and the President's lawyer in Nixon. He even had an uncredited role as a bedouin in Lawrence of Arabia, no doubt an opportunity to interview Sir David Lean.
Plimpton died in 2003. He has had many tributes since then, but one would think the most gratifying would be having an asteroid named after him. Here's the trailer to the film.