With her acrobatic soprano singing voice, little-girl speaking voice, diminutive profile (she’s 4 feet 11 inches tall) and relentlessly cheerful disposition, it’s hard to imagine Kristin Chenoweth unhappy. However, the 41-year-old dynamo—a native of Broken Arrow, Okla. and former first runner-up for Miss Oklahoma (1990)—is full of surprises. In Promises, Promises, a revival of the 1968 musical with a book by Neil Simon, she’s playing a young waitress whose affair with a married executive ends badly, so she tries to commit suicide (although she eventually finds a fresh start with another man).

“It’s very interesting for me to play someone who is the complete opposite of my public image, which is happy, happy, happy all the time,” chirps Chenoweth. “I am happy, but I have my down moments like everyone else. Still, it’s a real challenge to go to this kind of emotional place eight times a week.” The show’s music, by the legendary songwriting team of Hal David and Burt Bacharach, “is so fun for me,” she continues. “There’s nothing like being onstage singing ‘I’ll Never Fall in Love Again’ or ‘I Say a Little Prayer.’ I love what I do. It fills me up personally and professionally.”

Adopted at birth by an engineer and a nurse, Chenoweth sang at Baptist conventions when she was 12, and later found fame on Broadway in You’re a Good Man, Charlie Brown (1999) and Wicked (2003). Then she developed a legion of fans with her television work on shows including The West Wing (2004-2006), Pushing Daisies (2007-2009) and Glee (2009-2010).

She has written a memoir, A Little Bit Wicked: Life, Love and Faith in Stages (Touchstone, 2009), released three CDs and has appeared in movies, but Broadway is where she’s most content. Bonus: It allows her to spend time in New York City, where she has an apartment on the Upper West Side. “I always consider myself to be a New Yorker first and foremost,” she says. “Most nights, you can find me at Joe Allens in the Theater District, because I love the banana cream pie, or at Café Luxembourg on the Upper West Side. Just walking down the street in the city makes me happy.” Chenoweth also enjoys the spa experience. “I especially like Swedish massage, though I like to be rubbed a little harder than some other people,” she says. Crediting her youthful appearance with the fact that she’s not only petite, but also one-quarter Cherokee, she shares her beauty tips. “The key is not smoking, getting plenty of sleep and using vitamin E around my nose and mouth. Someone recently said he thought I was 26, but I’ve always told the truth, mostly because I’m a horrible liar.”

“I consider myself a New Yorker first and foremost ... just walking down the street makes me happy.”

While future projects include a new CD, a concert tour and another TV series, her short-term goal is to add balance to her life. “I don’t always get the chance to play as hard as I want to,” says the single actress, whose past paramours include Broadway star Marc Kudisch, violinist Joshua Bell and TV writer Aaron Sorkin. “I truly love my work, but I don’t rely on it for all of my happiness. I figure we’re only here on earth one time, so I might as well enjoy it.”