One night in May, near the end of a performance of David Mamet's smash Broadway hit Speed-the-Plow, Joe Mantegna saw a look of shock come over the face of his co-star, Madonna. "There was a man behind me," Mantegna recalls. Dressed in punk regalia, he came from the audience and climbed onto the stage. "He was obviously whacked out and moving toward Madonna." Joe's response was immediate and savvy: "I grabbed him by the arms and threw him into the wings." Then Mantegna the street-smart Chicagoan disappeared and Mantegna the award-winning actor snapped into action. While security men scuffled with the intruder, who was questioned and later released, Joe says, "I just spun Madonna around and jumped right back into the play."

Fortunately for Our Lady of Many Record Sales, Mantegna is not a stage virgin. After nearly two decades of musical road shows, regional plays and European touring, he arrived on Broadway in 1984 in Mamet's Glengarry Glen Ross and, as a sleazily endearing salesman, won the Tony for Best Supporting Actor, first time out. He has crammed eight, count 'em, eight films into the years since that breakthrough, playing everything from Compromising Positions' promiscuous periodontist to Cher's legal nemesis in Suspect to the cold-blooded card shark in Mamet's House of Games. Now Mantegna, 40, is back legit, creating the role of a money-grubbing movie executive seeking redemption in the arms of Madonna's ditzy office temp. "Corrosively funny," said the Wall Street Journal. "Flawless," raved the Washington Post.

"Brilliant!" shrieks pal Penny Marshall, bounding out of Mantegna's unpretentious, three-bedroom city sublet. No surprise that Marshall, in town to promote her new film, Big, has taken time to check in on Joe. He's not only an actor's actor, but an oasis of honesty among the dunes of Hollywood hype. "For a guy with that much talent," says his chum Peter Falk, "he could be a real jerk. He's not." Or, as friend Vincent {Moonstruck) Gardenia puts it: "What's unique about Joe is that he's normal."

So normal that when he heard he would be sharing a stage with Madonna, his first impulse was to invite her over with the mister—Sean Penn—for a plate of spaghetti. So normal that when he finally got together enough money to buy a house in Los Angeles, he wanted one "just like Father Knows Best." So normal that, rapidly readjusting to New York apartment living, he bellows through the walls to his wife, Arlene, 38. She's in the kitchen, directing a spoon toward the mouth of daughter Mia Marie, who is propped up in an infant seat in the middle of the table. Mia is the couple's miracle baby, born 12 weeks prematurely on June 5, 1987, when an infection of the placenta made a cesarean necessary.

That Friday night, Joe, at home in Los Angeles, had planned on attending a bachelor party for actor Richard Gilliland, who was marrying Designing Women's Jean Smart the following Sunday. Instead, the bachelor party came to St. Joseph's Hospital. "I was in the operating room with Arlene," Mantegna remembers, "and when I came out, I saw all these guys standin' there." All five were enlisted as godfathers to the 1 lb., 13-oz. newborn. Two days later, nervous Joe dashed out to stand up as Gilliland's best man, then back to the hospital, where Mia remained for three months.

Her survival was all the more precious because of the years her parents waited to have her. "We wanted to have money, a house, to do it right," says Arlene. "Fortunately for us, it worked out that way."

But the Mantegnas' road to riches was not a predictable path. Joe's Italian father sold insurance, while his mother wrapped packages at Sears; Arlene Vrhel's Czechoslovakian dad was an engineer, her mother is a telephone saleswoman for the Yellow Pages. Both grew up in the working-class town of Cicero, on the west side of Chicago. "In Cicero," says Joe, "you either look like me or like my wife. You're Italian or Slavic. Theater is not a mainstay of that environment." He got hooked by his drama coach, Jack Leckel, at Morton East High School. "Joe was a big star in all the musicals; was in the chorus," says Arlene. After high school Joe signed up as lead singer for the Apocryphals, a band that became well-known in the area. The two met again in 1969, when both were cast in the Chicago production of Hair. They lived together six years ("Who got married in the '60s?" asks Joe) before exchanging official vows in 1975.

In the early '70s, Mantegna connected with another important person—David Mamet. Mantegna's salty, staccato speech was music to Mamet's ear, and the Chicago playwright started writing with Joe in mind. "Part of what we have going," says Joe, "is that David is fascinated by the world I come from. He went to exclusive schools, yet he loved to hang out in pool halls."

This fall, Joe will be seen in another Mamet film, a comedy called Things Change with Don Ameche. Then he's scheduled for still a third, Homicide. "I don't know what it's about," Joe confesses. "David told me he just wrote the first sentence."

Whatever the role, it's bound to be a literate leap from those that Mantegna was accepting as recently as five years ago. Back then, he once found himself on the Los Angeles set of the TV series Mr. Smith, walking hand in hand with the show's star—an orangutan. "They wanted the ape to get used to me," he remembers, "so I used to walk around with him every morning, and I used to think—I had a lot of time to think, you know, because he'd stop, he'd have to go to the bathroom, he'd take his little pants down—and I'd say to myself, 'You know, my career is not panning out the way I thought.' "

A week later he got the call to do his first Broadway show. "It's the luck factor," says Joe. "Any good actor is just a phone call away from success."