“There’s a great West Wing quote that President Bartlett says to Josh [his deputy chief of staff]: ‘I want to be the guy; you want to be the guy the guy counts on,’” says Seth Sklar-Heyn sitting in his office at Foresight Theatrical. “I have made a profession of being the guy the guy counts on.”

Which explains why his name probably doesn’t ring a bell. But Sklar-Heyn happens to be one of the most powerful men you don’t know in show business.

Sklar-Heyn’s official title is Executive Producer for Cameron Mackintosh Incorporated, the billionaire producer’s right hand man in charge of his productions—and everything to do with them—in North America.

Sklar-Heyn is the production supervisor on The Phantom of the Opera on Broadway (the continual link between director Harold Prince and the production) and the associate director on the national tour of Phantom. The go-to for all things related to the longest running show in Broadway history, he watches the show in its entirety at least once a week, continually fine-tuning as it lives on. On top of that, he serves as executive producer handling marketing, advertising, budgets and more.

On the side, he’s the executive producer of the 2017 Les Misérables tour and now the executive producer and associate director on Broadway’s revival of Miss Saigon, which opened at the Broadway Theatre March 23.

“I think of myself as sort of a theatrical Michael Clayton: I’m a catchall, I’m a fixer,” says Sklar-Heyn. “If there’s an issue with an actor in performance, if there’s an issue with a wig, if there’s an issue with a costume, if there’s an issue with an ad, if there’s an issue with a press release, if there’s an issue with anything to do with a production—from nuts to bolts. Cameron takes full responsibility for every detail in his production, and, as a result, I’m responsible under him for every detail.

“I strive to surprise him and I strive to be ahead of him,” says Sklar-Heyn—but only so as to serve the art. “Cameron is relentless in his productivity.” The same can be said of his second-in-command.

So how does a 35-year-old end up number two to one of the most influential theatremakers in history?

At 16, through research for his Broadway-centric AP U.S. history thesis, he met director Stafford Arima. At 17, Arima recruited him to work on the original workshop of The Visit with Angela Lansbury. At 18, he launched the national tour of Parade and worked on the original out-of-town tryout Seussical. At 19, he was calling the show at Phantom on Broadway.

In the Broadway of yesteryear, as he calls it, Sklar-Heyn cut his teeth as a modern-day apprentice. “It was being open and exposed to those who came before,” he says. “I learned from Craig [Jacobs]; I learned from Barbara-Mae [Phillips]; I learned from Peter Wolf; I learned from Bonnie [Panson]; I learned from Clayton [Phillips].” All the way, he pocketed knowledge, like breadcrumbs on his way back home because as a kid growing up in West Hartford, Connecticut, Sklar-Heyn knew one thing: “I want to be in theatre. What do I want to do in theatre? No idea. It was just about being in the room and a part of the process.”

For a kid who just wanted to be in the room, Sklar-Heyn’s drive, willingness to learn, respect for the tradition of theatre, and passion for the art led him to a place where he runs the room.

And Sklar-Heyn wears the humility of that role like a badge of honor. “It’s Laurence [Connor]’s show. It’s Hal’s show. It’s Laurence and James [Powell’s] production of Les Miz. It’s Laurence’s production of Miss Saigon. It’s not mine,” he stresses. “I absolutely bring my taste, my style, to the table when teaching the show to new people, but I believe I have an understanding of what they want and they trust me.”

“I’m looking to support their idea, their vision, to translate what they want and make sure that’s what audiences experience,” he says. So he leads based on the philosophies and lessons gathered from the men he once admired from afar—Jack O’Brien, Andrew Lloyd Webber, Hal Prince, Trevor Nunn, Michael Grandage, Mackintosh—who are now his teachers.

“My relationships with the people that have taught me have been personal,” he confides. “Genuine connection,” he says, “it’s the only way I know how to work.”

“Hal comes in and sits with me every few months [at Phantom] and he writes [notes] down on notecards,” explains Sklar-Heyn. Afterwards, he communicates the notes to Sklar-Heyn and he tears them up. “That’s what I try to hold onto when I watch the show [alone]. You have to forget it all. You have to tear up the notecard.”

Sklar-Heyn emulates Prince’s approach to the theatre. “You have to watch the show as an audience member, you can’t watch the show as a supervisor,” he warns. In fact, Sklar-Heyn takes his cue from the book The Inner Game of Tennis. “Watch the ball. You’re not judging the ball, you’re not having an opinion about the ball, you’re just watching it and reacting to it.” With that mindset, he can step into an audience’s shoes even though he’s seen the show hundreds of times and knows it muscularly.

“My work is my life; it’s a lifestyle. It’s a vocation, like a priesthood,” he says. “It is 24/7. I never am not thinking about it. I feel guilty when I’m not in the theatre because I’m bred to work in the theatre.”

Sklar-Heyn is reticent to grant himself credit, yet he’s definitively proud of his accomplishments. He is cool and nonchalant, and ferociously and unquestionably devoted. He’s a realist, very matter-of-fact and, yet, when you watch him walk backstage at Phantom’s Majestic Theatre, a reverence and love for its history balances his authority. He is a study in the contradictions both he and Prince (who wrote the book on it) hold so dear.

Still, at 35, Sklar-Heyn has much ahead of him, but he’s not looking for a next career move. “It’s a lot when Trevor Nunn says, ‘What are you gonna do next, what do you want to do?’ When Michael Grandage says the same thing,” says Sklar-Heyn. “I could never have planned for any of this. People say, ‘What’s next?’ And I go, ‘Well, there isn’t a job like it.’”

Read More: HOW PHANTOM OF THE OPERA STILL RUNS FLAWLESSLY AFTER 29 YEARS