Nicholas Turturro misses New York City terribly. "Out here you get soft, you disintegrate," says Turturro in the living room of his Los Angeles home. Still, it's not all bad. He picks up a remote control, points it in the direction of his backyard and presses a button. Presto. Floodlights pop on, water cascades down white marble walls into an in-ground pool, and a Jacuzzi begins bubbling. He cracks a smile. "Pretty cool, huh?"

And pretty good for a guy who was schlepping suitcases as a doorman at Manhattan's St. Moritz Hotel as recently as 1993, when he landed the role of Officer James Martinez on a then-fledgling cop drama called NYPD Blue. On May 10 and 11, the "little sparkplug," as Blue costar Dennis Franz refers to him, puts his detective's shield aside to star as Mafia double-crosser Salvatore "Sammy the Bull" Gravano in a four-hour NBC miniseries Witness to the Mob (see review on page 28). Turturro says that playing a hit man turned FBI informant was not all that much of a reach. "I didn't grow up in the Mob world," says the 5'8" Italian-American. "But I am from Queens [New York], and I have a feel for these people."

Not to mention direct contact. There's his chum from Brooklyn: "He wasn't a hit man, but he was a strong-arm guy," says Turturro, 36. And there was also that night in the late '80s when prima don John Gotti, who is now serving life in prison for crimes exposed by Gravano, stormed into the St. Moritz lobby surrounded by wiseguys. "He looked menacing," recalls Turturro. "He really looked the part." Apparently, so does Turturro. "He was close to [Gravano's] appearance, and he had an understanding of the street," says Robert De Niro, who serves as Witness's executive producer.

Turturro's street smarts are abundantly evident on NYPD Blue, now in its fifth season, which he credits with turning him from pauper to prince. "I've gone from being a doorman," he exults, "to someone the whole world knows." Yet his colleagues say the hyperkinetic Turturro and the diffident Martinez are hardly alike. "Martinez is a big stretch for him," says Gordon Clapp, who plays Det. Greg Medavoy. "Nick is anything but shy."

Turturro's braggadocio, he says, comes from his father, Nicholas, an Italian immigrant and construction worker who, until he died in 1988 at 63, was "passionate about everything he did." The actor gets his artistic sensibility from his mother, Katherine, 75, a former jazz singer who still lives in the two-bedroom Queens home where her sons—Nick, Ralph, 45, a musician, and noted actor John, 41, star of Quiz Show, Miller's Crossing and Do the Right Thing—were raised.

Though he shared a childhood bedroom with John, Turturro says he and his brother tune to different frequencies these days. "John is sharp," says Turturro, "but he doesn't know it all. Sometimes he thinks he does, and we get into arguments. But I've always looked up to him."

The Turturro boys were introduced to acting in high school, where Nick made his debut in Guys and Dolls. But in 1983, put off by the pretentious productions, Turturro dropped out of Adel-phi University's theater program. "I didn't know what I wanted to do with my life," he recalls. So he became a doorman. A year later, Turturro married Jami Biunno; they had a daughter, Erica, now 13. (The marriage ended in divorce in 1995.)

But at his brother's urging, Turturro studied acting when he was off duty from the St. Moritz. The lessons paid off. In 1989 director Spike Lee hired him to spout racial epithets as a voice-over on Do the Right Thing and the following year cast him as a smarmy club owner in Mo' Better Blues. Nearly a dozen movie and TV roles—most as New York ethnics—followed. Things were evolving on the romantic front as well. In 1995, Turturro met flight attendant Lissa Espinosa while flying from L.A. to New York City. They married a year later and in 1997 had daughter Apollonia, 1. "Nick is a little rough around the edges," says Lissa, 29, about her husband. "But he has a warm, gentle side too."

If so, the machismo that has defined most of his oeuvre remains un-apologetically intact. Reflecting on his career, he recalls his "weird" college theater program. "It wasn't for me," says Turturro. "Everyone was running around in tights." Sammy the Bull should be proud.