On Halloween night, 1998, TNT aired a 24-hour marathon of the “Friday the 13th” movies, hosted by Joe Bob Briggs, who is, according to his website, “America’s Foremost Drive-In Movie Expert.” It was the latest episode of Briggs’s “MonsterVision,” a variety series that catered to the horror genre’s most dedicated fans.

Watching from Boston was Billy Thegenus, a teenaged film aficionado who sat transfixed as the identity of the first Camp Crystal Lake killer was revealed (spoiler: it’s not Jason). With that mind-blowing revelation, what was once an intermittent escape from the tedium of high school became an all-out obsession. Soon after, Thegenus gathered his weekly allowances to buy that original 1980 film on VHS. It was just the beginning of a growing collection of every “Friday the 13th” entry and a wealth of DVDs packed with commentaries and behind-the-scenes featurettes, none of which would go unwatched.

More than 25 years later, Thegenus has built a career on collecting and sharing movies with an audience wider than he ever imagined. Today, he is the programming and outreach coordinator for the Coolidge Corner Theatre in Brookline, New England’s most successful independent, non-profit cinema. Though the storied theatre has been open since 1933, it has always relied on the support and leadership of film romantics like Thegenus.

Last summer, the theater hosted Thegenus’s inaugural program, “Been Here For Years: Hip Hop at 50.” Featuring 20 films spanning the history of hip-hop, many of the screenings were accompanied by panel discussions from local scholars and artists, and concluded with an in-person Q&A with director Radha Blank, all headed by Thegenus.

“We put a program together that I felt didn’t automatically play the things that everybody expected,” he said.

Thegenus is always looking to curate a program that feels like more than just another string of movies. Among other hidden treasures, Coolidge showed Hype Williams’s previously hard-to-find jewel of ‘90’s Black cinema, “Belly,” on a 35mm film print. He wants every screening to feel like an event, the kind of movies that make audiences say, “‘Woah, I gotta show out for this because if I miss it, I don’t know the next time they’ll be playing it anywhere.’”

Despite his life-long love of movies, Thegenus never thought he would end up as a film programmer; the job wasn’t even on his radar until well into adulthood. He enrolled in the communication and journalism program at Suffolk University, the closest thing to a film production major the school offered. There, he joined WSUB-TV, a club dedicated to producing student films. Within his first year with WSUB-TV, he and his fellow members renamed the club to WSUB Productions, doubled the number of yearly productions, and secured a budget twice the size of the previous academic year.

A few years after his 2005 graduation, he began his journey at movie theaters with a part-time job selling tickets and concessions at the AMC Loews Harvard Square 5 in Cambridge. In the years to come he volunteered at the International Film Festival Boston (IFFBoston), where he fell in love with independent theaters like the Brattle. Thegenus joined the Coolidge team in 2017, thanks in part to a connection he made with IFFBoston’s program director, Nancy Campbell, who was also the Coolidge’s house manager at the time.

During the COVID-19 pandemic, he took a step back and reconsidered how he fit into the world of film. “I’m gonna really make an effort to lean into this much harder and not just work for a festival, or for a small theater,” he said.

At the Coolidge, Thegenus was never afraid to advocate for himself. His friendship with Mark Anastasio, the theater’s director of special programming, gave him the opportunity to voice his enthusiasm and a litany of programming ideas. By the time the outreach coordinator role opened up in 2022, Thegenus was the obvious choice.

Now, Thegenus says it’s hard to get bored.

“No day is typical. To be honest with you, a typical workday means that it won’t be typical at all,” he laughed. Due to the nature of film releasing, his work weeks begin on Friday and end on Thursday. And with programming, it’s all about forward thinking, sometimes months in advance. Thegenus and the rest of the team are currently developing the lineup of “After Midnite” screenings for October, allowing enough time to schedule, contact film distributors, and potentially secure 35mm or 70mm film prints.

As outreach coordinator, Thegenus wants to broaden the kinds of filmgoers that end up at the Coolidge. “I want to do whatever I can to get into other parts of the city,” he said. “Not just Brookline, not just Cambridge or Somerville. But I really want to get into every part of the city to just try to have people know what we’re doing and bring awareness to what we’re doing at the theater.”

But bringing people into the Coolidge doesn’t just mean more engagement with Thegenus’s programming; it also could be the measure by which the theater lives or dies. Thanks to the COVID-19 pandemic, over 2,000 screens closed across the country, and the number of cities without movie theaters continues to grow. Even the AMC Loews Harvard Square 5, Thegenus’s entrée to the theater business, closed its doors in July 2012; the massive Church Street building remains vacant to this day.

Independent cinemas like the Coolidge are a particularly precarious business, relying on donations and memberships to keep their community centers alive. “If you want to learn about cinema, if you want to really see a lot more movies, get a membership, support that place and go to the movies all the time,” he said. “Support your local theater, whatever that theater might be.”

Of all the films and series he has programmed, Thegenus’s greatest point of pride is more personal. “The biggest achievement in all honesty is not being shy, putting myself out there, and taking a chance on myself. Really trying to do something that’s bigger than me.” And he has the whole-hearted support of his partner. “She’s always open-minded, and she’s very supportive. I would have never even tried to go for this job if it wasn’t with her backing.”

The Coolidge Corner Theatre has hosted hundreds of events in its over 90 years of operation, but just before the pandemic hit, the man who unwittingly set Thegenus’s life with film in motion came to do what he did best: present some movies about rednecks. The Coolidge gave Thegenus the opportunity to meet Joe Bob Briggs. It was a full-circle moment for Thegenus, one that solidified that he was somewhere special: “It’s rare that you work in a place where you like everybody. It’s also rare in the place that you love what you do, but it’s even rarer when you get to do both.”

With a blockbuster summer coming fast, Thegenus has his work cut out for him, and he’s looking forward to whatever comes up.

“I’m really, really just really happy with what I do,” he said. “And there’s still room for me to grow. So there’s still beauty in it. I get to learn a whole bunch of stuff. I’m really very much excited to see what the next adventure is going to be.”