Deanna Witkowski is, in the words of an enraptured audience member at one of her shows, "the coolest Christian singing the hottest jazz." Not that you'd necessarily know Witkowski was a Christian if you slipped into one of her many late-night gigs in New York restaurants and clubs.

She does not thank Jesus when she acknowledges the audience's applause or say, as some Christian musicians have, that the next number is dedicated to a very special carpenter she knows. Nor does her self-financed debut CD, Having to Ask, betray her Christian commitment. But spend a few minutes talking to this 28-year-old Wheaton (Ill.) College graduate and you'll recognize a person whose faith flows as deep as the complex melodies and rhythms she bangs out on her piano.

"I don't really witness directly when I'm performing," says Witkowski. "What I find satisfying on a gig is when someone connects with the music on an emotional level. If people respect you for what you're doing artistically or professionally, then they'll build a relationship with you." Witkowski—young, white, and female—in no way looks the part of the proverbial New York jazz musician. Her lanky frame, frizzy red hair, and pale, freckled skin suggest a cross between a field hockey player and a grown-up Strawberry Shortcake doll. But hearing her play her instrument quickly quashes any doubts about her presence in the jazz world.

Her songs reveal an affinity for Cuban and Brazilian rhythms—a reflection of her studies under famed pianists Chucho Valdez and Hilario Duran—blended with traditional jazz and classical styles. The resulting sound is surprisingly mature, savvy, and confident. Indeed, she has been hailed by jazz critics as the real deal: "A major talent," ...