Every serious cinephile is aware of Stanley Kubrick, but far fewer are familiar with Leon Vitali, the English co-star of Kubrick’s Barry Lyndon who, following that performance, became the auteur’s steadfast right-hand man. Doing everything asked of him by the legendarily meticulous filmmaker—from taking notes, creating marketing materials, and color-coding prints, to casting, rehearsing with stars, and acting himself—Vitali was the irreplaceable assistant who helped shepherd to the screen The Shining, Full Metal Jacket and Eyes Wide Shut, even as his vital role in those projects remained largely hidden from the public.

That situation is justly rectified by Tony Zierra’s Filmworker, a superb documentary about Vitali’s career alongside Kubrick that serves as a case study of both selfless devotion and self-destructive mania—as well as a much-deserved celebration of a true artist-behind-the-artist. And according to its subject, it certainly doesn’t overstate how uniquely demanding it was to work with one of cinema’s true geniuses.

“Balance is a word that rarely came into my vocabulary throughout my whole time, whether I was working with Stanley or not,” Vitali chuckles when speaking to me from Los Angeles, two days before Filmworker’s premiere (this Tuesday) at the New York Film Festival. “I’m just one of those people who gets quite emotional once they got locked into something. And some things take on proportions of life and death.” Though he found watching himself on screen in this form “a little bit weird,” he confesses, “I can honestly say it didn’t exaggerate, in any stretch of the imagination, how fraught or tense it could be. Or how time intensive.”

As revealed by Zierra’s intimate portrait, Vitali and Kubrick’s relationship was a knotty one. It began on the set of Barry Lyndon, a 1975 period piece epic in which Vitali—a trained Shakespearean actor who, to that point, had enjoyed significant success on the stage and screen—was cast as the stepson of Ryan O’Neal’s title character. At one point, Kubrick had O’Neal and Vitali repeatedly re-do a scene in which O’Neal’s Lyndon viciously beats Vitali’s Lord Bullingdon, to O’Neal’s mounting horror—a moment emblematic of the forthcoming relationship between Kubrick and Vitali. When production neared completion, Vitali—enamored with Kubrick’s brilliance—asked if he might work alongside the filmmaker in the future. That request would lead to his eventual role as Kubrick’s veritable right-hand man, handling every major or minor task asked of him by the demanding director, be it coaching Danny Lloyd in The Shining (in clips, we see him literally running beside the camera, coaching the young star), or overseeing VHS box art and perfecting celluloid prints of past movies, each of which Kubrick insisted be personally inspected.

It was, in short, a dream job, albeit one that took many of Vitali’s confidants by surprise (since he was forgoing a promising acting career), and which eventually took an immense toll on his health, with round-the-clock toil—always on call, always managing the tiniest minutia—leading to multiple hospitalizations and severe weight loss. “When I started to talk to a lot of people, I started to realize, wait a minute, Leon was really in the middle,” Zierra says. “He was the filter. The go-between.” Yet the price for that closeness was considerable: loss of time with his family, risks to his well-being, and a subordination of his own identity. “What a story. Because you go in and want to talk about Kubrick, but then you realize that all that Kubrick has left is this kind of apprentice. He was so loyal to Stanley, but the guy almost didn’t exist.”

Convincing Vitali to participate in the documentary wasn’t easy, as Zierra soon learned. “I had an expectation in my mind [about Vitali], and then I found his address. He literally lives off Venice Boulevard in this tiny house. I pulled up, and this being just came out, and he looked like he’d been run over by a train. So done. He was almost like a helpless puppy,” he recalls. To overcome the man’s reticence, Zierra figured out a way to get his would-be subject talking. “I told him, ‘I’ll make you a deal—I’ll clean your house. I’ll put all your stuff away, empty all your boxes.’ That was me being savvy, in the sense of, if I clean everything, he’ll remember as we open boxes, and he’ll start to talk.”

The trick succeeded, and for the next three years, Zierra interviewed not only Vitali but also former colleagues, including Full Metal Jacket stars Matthew Modine and R. Lee Ermey, the latter of whom credits his role, and career, to Vitali’s efforts. Using a wealth of film clips and behind-the-scenes footage and photos, Filmworker gets as close to Kubrick as any previous documentary, presenting a warts-and-all snapshot of the director vis-à-vis his close bond with Vitali, who was responsible for (among innumerable other things) helping Kubrick decide to make The Shining, as well as performing in a variety of roles—notably, the Red Cloak in Eyes Wide Shut.

It was, by all accounts, a taxing partnership. But as Vitali says, it grew into its eventual form slowly, with new responsibilities emerging over time. “The nature of the profession, for want of a better word, is that it is, generally, a short-term tenure. So what was also to me a rather beautiful process was—you know, he’d spring something on me. During Full Metal Jacket, for instance, he wasn’t having much joy with layout for the newspaper and magazine ads. And so he just said, ‘Oh my god, you do something.’ So I did something, and he looked at it, and he said ‘Yeah, that’s it. That’s exactly what I wanted.’ So I had to do all the magazine and newspaper ads throughout the whole world, except the U.S. And it takes a long time! You’re going by millimeters—I’m not joking.”

Filmworker suggests that Vitali’s willingness to put up with Kubrick’s incessant, exacting demands was born from his relationship with his own father, a similarly kind-yet-volatile individual. Yet Vitali claims a more central reason for going to such lengths to please Kubrick was that he believed in the man’s greatness, and had to give as much to his vision as the tireless Kubrick did. “When some people talk about leading by example—well, it’s a nice idea, but you don’t quite get it. Then you come across somebody who gets it, but pushes it further past those lines, and doesn’t make it easy for himself – that’s the thing. He could be working until six in the morning, if we had a release day for Hong Kong, say. And we’d check every reel of every print before we’d let it go. A lot of people say, ‘Well, what’s the point, people don’t notice this or notice that.’ Well, the thing is, some people do. And more importantly, he did. And then, over time, I learned that you can’t escape it. If you see something is wrong, you’ve got to fix it. You can’t avoid it. It just becomes a bit of a mission, I suppose, but one that is fulfilling when you finally get to the end of it.”

Zierra agrees. “He saw what Stanley did to himself. Stanley did more things to himself than he did to other people. I mean, Stanley really pushed himself to death, to get the work done. So if Stanley is going to do it to himself…”

Moreover, Vitali simply craved the overarching experience of teaming with Kubrick on an undertaking, from start to finish—a desire he’d first felt when he was just acting. “Maybe I was just ripe for it. I wanted that totality of feeling that you get when you start a project, and then you’re there at the very end of it, and that includes distribution and everything.”

Even after Kubrick’s passing in March 1999, Vitali remained the doggedly loyal steward of his collaborator’s oeuvre, supervising the arduous process of restoring Kubrick’s movies, even when others—including those at Warner Bros.—grew tired of his painstaking methods. To Vitali, such steadfastness came, and continues to come, naturally. “If I didn’t [feel obliged to protect the movies,] I’d feel like a shameful hypocrite. Because I believe in it so totally. I really, really do. And I know that not every film is a Stanley Kubrick film. As some used to say to me, ‘He’s dead now, what does it matter?’ I used to pull what hair I had left out, just wanting to scream—it seemed to me such an illogical reasoning, especially when you’ve been a part of getting the work to where it is. That would feel like a terrible negation.”

To this day, Vitali regrets the long-worked-on Kubrick projects that never came to fruition, most notably The Wartime Lies, a drama about a Jewish woman’s survival of the Holocaust with the aid of Nazis that, he states, had “all sorts of nuances that I thought were so great, and would have been so beautiful to bring out. And we worked so hard on it, we really did. The day he decided not to do it, believe me, it was the quickest funeral you’ve ever been to in your life. He had these drawers where he kept these projects, and he just opened the drawer, looked at the script, and said ‘Goodbye to that,’ and off it went into a shredder!”

Furthermore, though he expresses respect for Steven Spielberg and his A.I.: Artificial Intelligence (a movie Kubrick had originated, and tried to make for years), he dubs that entire endeavor “a trap,” considering that there was just no way for anyone to truly duplicate what Kubrick might have ultimately achieved—both because his artistry was so singular, and because he often didn’t figure out how to shoot a given sequence until he was on set. Thus, any attempt by Spielberg to mimic Kubrick would have required “a 24-hour séance,” he laughs.

In the documentary’s most heartbreaking sequence, Vitali is both not consulted on, or even invited to the premiere of, the Los Angeles County Museum of Art’s (LACMA) 2012 “Stanley Kubrick” exhibit—an insult of the highest order for a man who was so crucial to Kubrick’s final three decades. To Zierra, that’s part and parcel of an industry that has little respect for the myriad men and women whose unheralded contributions make the industry—and celebrated artists—thrive. “No one wants to sit and talk about the janitor, or the grip guy. They’re not important. It’s a status thing. That’s why Leon wasn’t invited to LACMA. Not because people hated Leon,” he stresses. “So the whole point of this documentary, as Lisa Leone says in the movie, is [to highlight that] it’s the people below the line who are the ones that elevate the people above the line.”

A film of both formal gracefulness and intense compassion that digs deeply into the way acquiescing to another’s vision can be both insane and insanely rewarding, Filmworker movingly lionizes Vitali as an essential component of Kubrick’s work, and legacy. For his part, Zierra isn’t sure that, with Kubrick now gone, Vitali will ever quite be the same. “It’s almost like Stanley basically built Leon from scratch. He molded and shaped Leon to be a devoted spokesperson and guy behind him, because at the end of the day, the movie is what mattered. And Leon learned that. I think Leon got so buried inside that, he has no idea what the hell happened. And I don’t think he’ll recover.”

Talk to Vitali, however, and he sounds not only still devoted to the late filmmaker, but deeply proud of what they accomplished together. “When I started Barry Lyndon, I had one dialogue scene, that was all, and a couple of poncing-around and looking like a spoiled young brat [scenes],” he remembers with audible joy in his voice. “But from the first moment I met him, I thought it was going to be more hero-worship, and it wasn’t. You got talked to like an adult. You know, I was a young actor, and he spoke to you as if you should know everything that we’re trying to do. So it wiped away the luster of ‘Ooh, I’m acting in a Stanley Kubrick movie.’ It was, in the end, driving you as well. You weren’t acting anymore; you were being. And there’s a big difference. It was wonderful.”

And as for whether old habits die hard? “I brought him to see a rough cut [of Filmworker], and I could see that he’s been programmed by Stanley,” says Zierra. “Because there was this ticking sound that I was still working on, and he was like ‘I hear a tick! I hear a tick!’ But that’s what makes Stanley’s movies beautiful, and so amazing—is that everyone gave their best, whether they liked it or not.”

Like mentor, like apprentice.