For the actor Daniel Radcliffe, Harry Potter was the role of a lifetime. Over eight movies and a decade that spanned his entire adolescence, Radcliffe became the world-famous face of the bespectacled boy wizard. While the franchise, now set to retell the core story as a TV show with a brand-new cast, continued on without him, Radcliffe’s early success gave him the freedom to pursue quirkier parts like a farting corpse or Weird Al Yankovic. 

For stuntman David Holmes, Harry Potter also changed his life — in equally irrevocable, yet more complicated ways. In January 2009, while filming a scene for “Harry Potter and the Deathly Hallows – Part 1” as Radcliffe’s double, Holmes broke his neck, an injury that left him permanently paralyzed. Radcliffe and Holmes were friends on set and have remained close ever since, a relationship that forms the core of the new HBO documentary “David Holmes: The Boy Who Lived.”

“Harry Potter’s a big thing for a lot of people, and nobody knows what happened to me,” Holmes says early on in “The Boy Who Lived,” which both Holmes and Radcliffe executive produced alongside director Dan Hartley. “This is the story that matters the most to me from ‘Potter,’” Radcliffe says near the film’s end. What lies in between is an attempt on Radcliffe’s part to use his fame to shed light on his friend’s story — and navigate the complex mix of guilt, motivation and admiration spurred by the two men’s contrasting, interwoven fates.

As a child on the set of the first “Harry Potter” films, Radcliffe looked up to the slightly older Holmes, a trained gymnast who broke into stunt work with the 1998 movie “Lost in Space.” A risk taker by nature (he describes his former philosophy as “you’re only living when you’re nearly dying”), Holmes eagerly took to onerous tasks like multi-story falls or “flying” a broomstick for hours on end. He also mentored Radcliffe in matters like how to swing a Quidditch bat, likening his position to that of a PE coach. 

The first third of “The Boy Who Lived” is illuminating, both about Holmes himself and the nature of film sets writ large. The tabloids may have focused on Radcliffe’s relationships with co-stars Emma Watson and Rupert Grint, the actor reflects, but “the people I was closest to were all people from the crew” — the makeshift families that form in ad hoc workplaces, unbeknownst to the public. The job of most below-the-line labor is to render themselves invisible, creating a seamless experience for the viewer who will never see what they’ve sacrificed in the name of entertainment.

Holmes’ injury transformed his life, instantly ending the career he’d previously pursued with single-minded dedication. (He does offhandedly mention the studio’s insurance policy meant he was taken care of financially, which comes as a relief.) Radcliffe finds faint echoes of his friend’s struggle in his own experience, post-Potter, of feeling lost without a sense of structure or direction. The comparison never feels like Radcliffe is equating his first-world problems to Holmes’s life-altering condition. Instead, Radcliffe emphasizes that what happened to Holmes gave him the perspective “to know how random and fleeting everything could be,” and not to waste opportunities he had the privilege of still being available to him. 

“The Boy Who Lived” is nonetheless most affecting when it confronts the more uncomfortable, less overtly inspirational aspects of its story. Holmes shows remarkable perseverance through many surgeries and an ongoing loss of mobility, working to stay involved with stunt work via education and raising funds for treatment centers. He’s also bluntly honest about the mental toll of his paralysis, comparing it to “a prison cell” and being “stuck in a coffin.” A particularly wrenching scene sees Holmes reunite with “Harry Potter” stunt coordinator Greg Powell, who once considered Holmes a surrogate son but admits to avoiding him out of shame, having supervised the fateful accident. “I fucked his life right up,” Powell sobs, though Holmes argues he knowingly went into a dangerous line of work.

The documentary works to introduce its audience to Holmes, who proves deserving of the spotlight. But they’ll go in knowing Radcliffe already, and as a result, it’s the star who feels most illuminated by “The Boy Who Lived” despite his efforts to train our attention on Holmes. (During a tour of his London flat, Radcliffe admits he’s never let a camera crew into his residence before.) Throughout the film, Radcliffe shows a child actor’s sense of bemusement at the glamorous, exploitative, amazing, capricious industry he was thrust into before he could really understand it. As an adult, Radcliffe knows the system that rewarded him so lavishly is fundamentally unfair, so he works to change what he can and make peace with what he can’t. “It was an incredible 10 years,” he says. “That can all be true — and this terrible thing happened to Dave.”

“David Holmes: The Boy Who Lived” will premiere on HBO and Max at 9pm ET on Nov. 15.