Alex Weisman’s place is in disarray. Wearing a faded black T-shirt, shorts, and flip-flops, the actor maneuvers around piles of half-filled boxes as he makes his way to the deck of his Lincoln Park townhouse. It’s a warm, sunny September afternoon, and he knows it’s a final moment of calm. In two days, Weisman, who’s 30 but could pass for 20, will move to New York City, where in the spring he will make his Broadway debut in the much-anticipated play Harry Potter and the Cursed Child. “This is just, like, my dream come true, to be on Broadway,” he says. “I say to my mom, if this happened to me when I was 23, I would have turned into a monster.”

For Weisman, the career highs keep getting higher. Last year, he enthralled audiences and critics in the dual role of Jason, a troubled young churchgoer, and Tyrone, his foulmouthed, devilish alter ego hand puppet, in Victory Gardens’ Hand to God. The Tribune named it one of the year’s top 10 performances, and Weisman snagged his fourth Jeff nomination (the winners will be announced November 6). “You can feel him when he’s onstage,” says Nick Bowling, TimeLine Theatre’s associate artistic director, who cast Weisman in his Jeff-winning breakout turn in The History Boys in 2009. “He brings his physical and emotional life to light onstage, and that’s rare.”

In November, the Northwestern graduate will return to Chicago to lend his formidable talent to a role that hits close to home: Jordan Berman, the perennially single 20-something in Joshua Harmon’s Significant Other. “Jordan is a Jewish gay man who’s physically imperfect and self-loathing, which I’m quite familiar with,” says Weisman. “I struggle with my weight like it’s my job. I’ve spent so much of life thinking of my body as my enemy.”

And he’s not talking just in terms of watching the scale. Weisman has a congenital heart defect: He was born with three valves instead of four. When he was a few months old, he had the first of three open-heart surgeries. As a result of his condition, he was such a docile toddler that a talent agent took notice and told his mom he’d make a great kid model. That led to commercials, and after he saw his older sister, Robin, play the titular lady in the 1990 movie Three Men and a Little Lady, Weisman was hooked on acting at age 4. He likes to joke that he will spend the rest of his life “trying to be as famous as my sister when she was 5.”

Weisman will eventually need a fourth surgery, but day to day he’s fine physically. Not that there haven’t been scares. Two years ago, his physician spotted an abnormality on his echocardiogram and told him he had to be hospitalized right away. Weisman’s response? “I’m opening a musical tomorrow night.” The doctor reluctantly agreed to let him perform in October Sky at the Marriott Theatre as long as he wore an antibiotics-dispensing intravenous port, which the show’s costume designer artfully hid. Weisman missed just two performances.

But even the normally unflappable Weisman found himself despondent after the January inauguration. Seeking solace, he turned to books. Specifically, Harry Potter. He finished the seven-book series in February. The day after, his agent emailed. He wanted Weisman to audition for the part of a kid in the Broadway show, which depicts the wizard as a dad. Weisman had seven auditions over the next five weeks; he paid his way to New York each time. (An acting teacher at Northwestern once offered sage advice, he says: “Get a credit card that’s linked to an airline.”)

While Weisman says he doesn’t know if he’ll stay in New York past the show’s run and insists that he’ll always identify as a Chicago actor, Bowling thinks otherwise: “I’ve joked with him that in a few years he’ll come back to do a show and he’ll be a big name.” A big name, perhaps, but one who remains in competition with the legacy of a 5-year-old.

Go:Significant Other runs November 3 to December 9 at Theater Wit, 1229 W. Belmont Ave. $15 to $38. theaterwit.org