Justin Cooley was just moving into a dormitory for his freshman year at Texas Christian University when he got the call: Did he want to forgo the whole college thing and instead take a role in an Off Broadway musical with a strange title and an even stranger subject?

Cooley was an 18-year-old Kansan who had never been to New York, let alone seen a Broadway show, and he had never even worked on a stage production alongside grown-ups.

But opportunity, to quote Stephen Sondheim, is not a lengthy visitor. Cooley grabbed the role, moved to New York, and hit the aspiring-actor jackpot: The musical, “Kimberly Akimbo,” transferred to Broadway, where he’s featured as an anagram-obsessed, Elvish-speaking, sweetly weird high school student who befriends a teenage girl braving a life-shortening genetic condition while living with a comically dysfunctional family.

“This is not the path I thought I was on,” Cooley, now 19, told me over a cheat meal at a Downtown Brooklyn burger-joint-cum-video-game-parlor, 8-Bit Bites, with a retro aesthetic that a publicist suggested as the perfect setting for an interview since Cooley is an avid gamer and “Kimberly Akimbo” is set in 1999.

Full disclosure: I had suggested meeting the actor somewhere that was colorful and relevant and might jostle free some delightful and revealing details for this article, but it turns out that asking for location ideas from a teenager who just moved to New York is not the best strategy. When I got to the restaurant, I learned that Cooley had never been there before. And I’m not a gamer, so the production’s fantasy that we would play Super Mario and that would lead to a charming anecdote for this article instead led to, well, whatever this is.

But no worries: It turns out that Cooley is as wide-eyed and winning as his character, Seth, who, despite a serious case of adolescent awkwardness and goofily geeky obsessions, is the most grounded person in a cast of schemers and dreamers, all of whom seem a little lost.

Seth is sort of a stand-in for David Lindsay-Abaire, the Pulitzer-winning playwright (“Rabbit Hole”) who wrote “Kimberly Akimbo” two decades ago as a drama, and then, partnering with the composer Jeanine Tesori, adapted it into a musical.

“I’ve only recently started to admit that Seth is as close as I’ve ever gotten to putting myself in a play,” Lindsay-Abaire said. “That kid is essentially who I was at that age.”

Cooley didn’t have to dig too deep to find his inner Seth. One detail pretty much tells you all you need to know on that front: He spoke excellent Elvish at his audition. “He nailed it,” Lindsay-Abaire said. “Whether he knew Elvish or not, he just went for it, and that was the thing that put it over the top.”

Here’s Cooley, defending his geek cred over the clamorous strains of Donna Summer and chiptune: “People definitely thought I was weird, because of my eccentric interests. I wore anime shirts, and I was a theater kid, and I was friends with all the girls who had rainbow hair.”

He collects manga, has dabbled in Dungeons & Dragons, and is especially fond of old-school Nintendo games — “your classics, like ‘Mario,’ ‘Kirby,’ ‘Legend of Zelda,’” he said. “And Pokémon. I’ve been playing that recently. I’ve never grown out of those phases, and don’t know if I ever will.”

Cooley, who finds echoes of his own curiosity in his character, said he also loves the way his casting might upend some stereotypes. “To play the role of Seth as a Black person is just so emotional for me,” Cooley said. “To see a Black kid who is weird and loves Dungeons & Dragons and all this nerdy stuff and is highly academic and he’s not a class clown, he’s not athletic, he’s not cool, he’s just himself — that’s exactly how I felt growing up.”

HOME IS OVERLAND PARK, Kan., where Cooley was a choir kid with no stage experience when the theater program at his suburban high school came looking for Black students willing to join a production of “Hairspray,” a musical that concerns race relations. Cooley wound up in the ensemble, and was hooked.

“By my senior year, I realized, I had done so many shows,” he said, “and I was like, ‘Oh crap, I think I actually want to try doing this as a career.’”

He won a prize — outstanding actor in a lead role — at the Blue Star Awards, a musical theater competition for Kansas City-area high school students. That, in turn, landed him in the Jimmy Awards, which is the national competition, and though the event was virtual, it was still life-changing: Cooley sang a song from “Tuck Everlasting,” and became a finalist.

“With Spotify cast albums, high schoolers these days in musical theater latch on to anything and everything,” Cooley said when I asked how he chose “Tuck,” which lasted only a month after opening on Broadway. “I’ve never seen the show, ever. I have no idea what it’s actually like. But I love it.”

This is the thing to know about the Jimmy Awards: They’ve become an important pipeline for teenage performers. Casting directors pay close attention, looking for promising talent. And that’s what happened to Cooley.

“Justin was really special: he was so vulnerable and so accessible, and even if he didn’t have the largest Elphaba range, he was so good,” said Bernie Telsey, a powerhouse casting director on Broadway and in Hollywood, and a longtime Jimmy Awards judge.

At first, when Telsey reached out about “Kimberly Akimbo,” Cooley demurred. He had a big role in a community theater’s student production of “Mamma Mia!” He was sick with mononucleosis. He was overwhelmed.

Telsey persisted, and Cooley reconsidered; he was intrigued by the involvement of Tesori, the show’s composer, because he had seen a local production of her Tony-winning work, “Fun Home.” “I knew it had to be something good,” he said.

So the third time the casting office asked him to audition, he made a tape at home — his mother read Kimberly’s lines, and he performed as Seth. Then came an online callback, a first trip to New York for an in-person audition, and an offer — for a short run, Off Broadway, but still.

“I was with my mom,” he said. “She screamed, and called my dad. I sat down for a sec, and was like, ‘No way!’”

He put college on hold. “I deferred for a semester; I told my friends, ‘Oh, I’m going to do this fun little show downtown for a bit and then I’ll see you all.’ No one really knew where it was going.”

IT WAS GOING WELL. The show, which opened in a 199-seat theater at the Atlantic Theater Company in late 2021, garnered strong reviews, and announced a Broadway transfer.

“I was like, ‘Oh, gosh, I guess I’m not going back to college’,” said Cooley, who until his senior year had thought he might try to become a psychiatrist. “‘I’m just going to ride with this.’”

And it’s been quite a ride.

“I wonder how other people my age who come to Broadway deal with it,” he said. “I had never done a job outside of a high school setting. And it was a new musical, on top of that, which I had never done, so I had to get used to having my own input, because we were creating a character.”

He has turned, often, to the show’s star, Victoria Clark, for guidance. She’s a 63-year-old Tony winner (for “The Light in the Piazza”), and he’s a 19-year-old novice, and in the show they both play high school students who are about 16 years old. “It was incredibly intimidating,” Cooley said. “I thought, ‘Oh God, she’s so experienced. She’ll probably be irritated by my amateurness.”

Instead, Clark has become some combination of mentor and friend; before each show, the two share a quick hug at the skating rink counter where his character works. “Of course I’ve felt very maternal toward him, but I’ve tried to put that aside, and I’m also aware, with my 40-plus years on Justin, that there could be some kind of power dynamic, but I’m super-conscious about that,” Clark said. “It wouldn’t make any sense to cast someone who was more experienced, because it would seem false, and with Justin there is a truth and beauty to his performance that I have to match. In many ways, he’s been my teacher.”

The show’s director, Jessica Stone, was originally hesitant about casting Cooley, because he was so green, but she said he has been an eager student, at one point pulling her aside to ask the questions he was nervous about asking in front of everyone. And she said the Clark-Cooley dynamic has paid off. “His youth and sweetness and openness, and his lack of the life that weathers us all, washes over Vicki,” she said, “and Vicki’s years of skill and work and experience wash over Justin.”

He’s had a lot to learn, and not just about easing up on the burgers and steaming his vocal cords. “I had to learn to feed myself,” he said. “How to not stay up late and play video games. It definitely took a step up in maturity for me to be working in the professional world. I’m still figuring out a lot of things.”

Tesori remembers a day when she ran into Cooley on his way to Trader Joe’s and he blurted out “Hey, how do you cook?”

Cooley is the youngest person in the cast, and that can be isolating. “I’m surrounded by people who are not in the same life stage as me,” he said. “Victoria Clark is my best friend. But I’m working on it — I have a grand total of two friends here, outside of my cast, and that’s good for me right now. I’m pretty great with independence and alone time.”

In that free time, he draws, practices guitar, and, of course, plays video games. On social media, he sees his friends from home, “in college, at frat parties, and I’m like gosh, I’m drinking tea and going to bed. It’s a lot — a personal journey at a time where I’m obviously still growing and changing every day.”

So what’s next? He wants to talk composing with Tesori, and writing with Lindsay-Abaire. He thinks about going back to school, but also about sticking with acting. “There’s still so much ahead that it can be scary,” he said. “This show teaches me every day to not get ahead of myself, and just enjoy now, because there’s no gift like the present.”