Although Tesori grew up next door to Manhattan in Long Island, she wasn’t a musical-theatre kid. She calls herself a “Title 9 girl” who played sports like field hockey and lacrosse. The only reason she’d come into the city to see shows was to ditch school with friends. She saw the original production of A Chorus Line this way in the standing-room-only section. (She still remembers the pain from the platform boots she wore.)

She was always gifted musically, however. She started taking piano at a young age and would make up songs with her three sisters. But when she hit her teenage years, she rebelled.

“I quit piano when I was 14 because I had had enough of what was trying to be impressed on me,” Tesori says. “Do I look like a concert pianist? I can’t play for an hour. You have to put an egg timer on to make sure I stay in place. I keep time by chewing bubble gum. Do I look like a concert pianist to you?” she repeats for emphasis. Still, she admits, “It was a very strange rebellion for me. I thought, ‘Oh, people really don’t know who I am. I don’t know who I am, but they really don’t know. Music isn’t who I am.’ So I left it.”

It wasn’t until college at Barnard, where Tesori enrolled as pre-med, following in the footsteps of her doctor father, that she rediscovered both her love of—and talent for—the arts. “I went to school in New York in two schools—one was uptown at Barnard and the other was downtown watching musicals,” Tesori recalls. “I saw everything. And when I saw one thing, I would see it 13 times. I felt like theatre was the thing that was waiting for me. I discovered it at a time when I was ready.”

She changed her major to music, which meant registering at Columbia because at the time Barnard didn’t have a program. She credits her Sicilian grandfather, who was a conductor and composer in Italy before moving to the States, for her musical genes. (She still has his baton, music stand and arrangements.) When she was looking for a job one summer, she found a listing for Stagedoor Manor and she applied to be a pianist, which planted the seeds of her future career.

“My friend and I did a production for kids at Stagedoor, and we needed songs. We couldn’t find any, so we decided to write some,” Tesori recalls. “And then my friend said, ‘You know, these are pretty good. Have you ever thought about songwriting?’ And I said, ‘No. I don’t know what that is. It’s just about putting words to music.’ And she’s like, ‘That’s what songwriting is.’”

But Tesori’s process goes beyond songwriting. “Whether she wants to direct or not, Jeanine is a director. She directed Caroline in the music,” says Tony Kushner, who wrote the libretto for Caroline, or Change, which he calls “without question the most pleasurable creative experience of my life.” He explains: “When Jeanine sets something, she sets its emotional geography along with this kind of astonishingly beautiful music. If you just do what she wrote, the thing is kind of fool-proof. She gets the piece on a very deep level, and she gets its theatricality. There’s such a difference between a really great composer and a really great theatre composer.”

Though she claims to not think about it, Tesori experiments with theatrical form from show to show. For example, Caroline is sung-through, while Shrek is a relatively conventional big-budget musical comedy. What Tesori emphasizes is her commitment to how the structure serves the story and the characters. Almost all of her collaborators—Kushner, Kron and Shrek’s David Lindsay-Abaire—were successful playwrights and first-time lyricists and book writers when they joined forces with Tesori.

“She taught me everything I know about musicals,” says Kron. “She helped me to understand how lyrics are different from dialogue. She likes to work intuitively. She’s wary of any kind of ideas about musical theatre that turn dogmatic, but at the same time she has a very deep understanding of the structures of musical theatre.”

Writing musicals is very personal for Tesori, and like most writers, she needs to find a “way in.” For her, that way is through stories about unlikely musical-theatre characters—outcasts on the fringes of society whom she wants to bring to the forefront. “I’ve always felt like an outsider,” Tesori admits, and, highlighting another theme from her musicals most fully realized in Fun Home, she adds, “I obviously have a very complicated relationship with my father, and I think that’s why I write those stories.”

As she talks, Tesori reiterates the importance of continuous learning. “I need to be around people who have something to teach me, because it makes me feel like I’m not getting old,” she jokes. Even though she’s usually on the more experienced side (at least in a musical sense) of her writing teams, she never enters a room claiming to know everything. Her open-door policy and flexibility make her an ideal partner, according to almost everyone who’s worked with her. Some of her collaborators are even slightly possessive (in a good way). “There’s nobody else I enjoy working with more,” Kushner gushes. “I always have a little bit of a twinge when she’s working with somebody, especially somebody I really admire, like Lisa Kron. And of course when I watched Fun Home, I won’t deny that I felt jealous, but also just thrilled, because I think that’s such a spectacular musical.”

The stories Tesori gravitates toward don’t always have the mass appeal of branded entertainment (with Shrek being the marked exception), and though it’s hard to describe her as anything but successful, she says she’s after a less mainstream definition of success.

“I’m not a blockbuster writer. I’m not going to be a blockbuster writer. I know that about myself,” says Tesori. “I’m never going to have a big Wicked. It’s not who I am. That’s fine for me. It will always mean I have to write a lot to make a living. I’ll always be doing a lot of things because it’s not in my destiny to have that one big show. It’s also not what I’m chasing.”