INTERVIEW : She’s No Mere Sister Act : Laurie Metcalf is known to TV fans as sibling to the turbulent star. Now she’s traveling about 3,000 miles away from Roseanne. But it’s not what you think. (Really.)

A lot of factors have accounted for the success of the 7-year-old “Roseanne” show, begin ning with the mercurial--to say the least-- star herself.

The comedy series was the first of its era to show a representative class of working stiffs left out of the golden glow of “Morning in America”--as if the decade had finally wised up to the Huxtables’ semiprecious role modeling. And the show has evolved. Its intuition tells us that if the principal blue-collar strains of the late 1980s were economic, those pressures have imploded into ‘90s family life.

Too, the show’s producers had the good sense to surround Roseanne, an acting amateur, with solid pros, particularly John Goodman and Laurie Metcalf. Goodman’s gregarious face and hefty frame have become a familiar sight on TV and the big screen. And serious “Roseanne” watchers have a particular regard for Metcalf’s Jackie, who can never seem to get herself out of harm’s way.

“I like to play a wide range of characters,” Metcalf says. “The more they’re unlike me, the better I like it. But Jackie is so close to my own personality that I still feel self-conscious playing her. She’s someone I haven’t solved.”

Fans, especially women, recognize in Jackie a quick intelligence and an appealing, voluble alertness, an optimistic view held firmly in the wrong direction and a woman who is author of her own disappointment. The first to show up at the door to help out in a crisis (when she isn’t announcing one of her own), she enters to make things worse, to inject her own complexes into complex matters. You have to love her spunk.

More professional observers see in Metcalf a superb actress at work. From a hairstyle that looks as if it were cut in a fan blade to a body that appears stressed even in wiry repose, Metcalf’s presence alone conveys Jackie’s imbalances. Beyond that, she has clear-water emotional transparency. Every conflicting emotion is visible in her face, and she has a capacity, rare among actors, for active listening.

“I’ve learned so much from her,” says Roseanne. “She’s from a theatrical tradition. I’m from stand-up. It’s a different approach. She was very helpful to me in the beginning. She works in her own way, but it pulls everyone together. She’s just awesome.”

“My first impression of her was ‘My God, this woman will do anything,’ ” says John Goodman. “Her strength stems from her commitment to a role. She’s my rock. I have an amazing capacity for self-pity, but when I get that way I just look at her and see how she slides through effortlessly. The choices she makes are astoundingly brilliant. She won’t go for the safe or the tried-and-true.”

Such honeyed tribute is the norm among show-biz ensembles, which tend to be self-protective. But from “Roseanne’s” tempestuous beginning, with its steady report of hateful hates and conversations with flying plates, you can detect a note of genuine appreciation from veterans of the carnage who would look back wearily and say, “Well, there’s always Laurie.” As though, by standing above it all with statuesque inscrutability, she offered comfort.

Metcalf is off to New York during hiatus to play a wife betrayed in Alexandra Gersten’s “My Thing of Love,” opening May 3 at the Martin Beck Theatre. And, in a rare gesture of solidarity and affection, some “Roseanne” cast members have taped a number of commercial TV spots, now airing in New York, to help get the word out: From the “Roseanne” set Goodman offers her avuncular notes on how to conduct herself as a star. Estelle Parsons, who remains in character as Jackie and Roseanne’s mother, begs for tickets to any Andrew Lloyd Webber musical. And Roseanne wonders aloud just how long Jackie’s “love thing” really is.

The spots are funny. The play--which deals with the love triangle of a husband (Tom Irwin), his wife (Metcalf) and his mistress (Sheila Kelley)--is not. But it brings Metcalf back not only to a role she created in 1992 in Chicago but also to the thing she may do best--theater. She’s a three-time Emmy Award winner for her support on “Roseanne,” but nothing matches the superlatives she has earned for her stage work (she last appeared locally in a 1992 production of “Wrong Turn at Lungfish” at the Coronet Theatre).

It was Metcalf’s Obie-winning performance as the prostitute in a 1984 New York production of “Balm in Gilead” that created sufficient buzz to reach the ears of “Roseanne’s” casting directors.

“(Producer) Marcy Carsey told us about her before the show was cast,” Roseanne recalls. “She said, ‘We’ve got the greatest actress in the country to play Jackie.’ We were psyched.”

“It’s like having Michael Jordan on your team,” says “My Thing of Love” director Michael Maggio, associate artistic director at the Goodman Theatre and a 1994 Obie winner for “Wings.” “Her emotions are so accessible to her. All you need to do is create an environment for her to do what she does best, then let her go.”

It’s hard to tell what Metcalf thinks of these kinds of accolades; that is, if she disbelieves them or doesn’t think she deserves them or writes them off as the requisite celebrity backslapping accorded anyone riding a hit show. From her demeanor, it appears almost as if they belong to someone else (when she discusses her characters, she often looks pointedly away, as though they were rounding a corner down the street).

She is nothing if not self-effacing.

“I almost never give interviews,” she said recently during a rehearsal break in North Hollywood. “It’s not because I want to play hard to get. It’s just that I never seem to have anything interesting to say.”

This is partly a regional characteristic. Metcalf was born in Carbondale, Ill., and raised in Edwardsville, a small town (pop. 10,000) not too far across the Mississippi River from St. Louis. To the northeast lies Chicago. To the west, you would have to feel, lies Lake Woebegon or similar hamlets where immodesty ranks as a capital offense.

At 39, Metcalf is the oldest of three children. Her father was comptroller at Southern Illinois University. After he died in 1984, her mother went to work as a librarian. Metcalf’s childhood and the place she spent it in were held in such long seasons of quiet non-event that they are difficult for her to remember.

“It was fun in the summers,” she says. “We biked. At home it was gather ‘round for ‘The Ed Sullivan Show.’ No big trips. A big trip would be to the Ozarks. A really big trip would be to New Orleans.”

The actress’s personality seems sturdily constructed out of the cardinal Midwestern virtues of laconism, moderation, sincerity and a bone-deep conviction that self-reference constitutes the height of vulgarity. Even her dry laugh is an expression of watchful restraint. Not a promising portrait of a young artist.

“I was an office secretary for a long time,” she recalls. “A good secretary,” she adds, with an uncharacteristic note of pride, as though she’d be willing to take a letter on the spot and would have it back to you in minutes, with perfect spelling and punctuation. “I thought my acting career would consist of going over to St. Louis for one audition. I’d get turned down, and I’d never go to an audition again. Acting seemed like such an impractical thing to do.”

A few weeks before she left for New York, she was sitting at an outdoor table of an Italian restaurant in a nearby strip mall, dressed in faded jeans, scuffed-up running shoes and a white T-shirt embossed with small colorful shapes of whales. An unprepossessing figure, pale, dry, pleasant, businesslike. Nothing wasted or impulsive.

“I was shy,” she says of her early life in Edwardsville. “I wasn’t a curious person. I was content to be a good student and do everything by the rules. I was conventional, practical. I lived a structured life, where you can see your accomplishments. I think my personality is more suited to that.”

To gain some idea of what life in Edwardsville must have been like, one of the first things that struck Metcalf when she went off to college was the strange, almost foreign accents of her new classmates. This was at Illinois State University, in the distant realm of Normal in the central part of the state.

Metcalf was a German major (for a while, she thought she would become an interpreter), then switched to anthropology. As a sweet treat for her academic rigors, she went over to the theater department and signed up for a role in Joe Orton’s “What the Butler Saw” and discovered that she had absolutely no stage inhibitions--in this instance, she had to walk out in her underwear.

“Theater opened up a whole new world for me,” she says. “It was a freedom I’d never known before.”

A young man named Terry Kinney, prominent in the school’s drama department, caught one of Metcalf’s performances and predicted a big future for her. She became just as warmly disposed toward him; they began dating.

Kinney and several of his friends had been holding earnest discussions about starting their own theater. In 1976 one of them, Gary Sinise, struck an irresistible deal with a Catholic school in his hometown of Highland Park, about 25 miles from Chicago up the Lake Michigan shore. For one dollar a year, they could make their own theater in the school basement.

“Basically we wanted to control our own work and not be at the mercy of conditions most actors have to go through, going to New York or Los Angeles and working as waiters while waiting for a break,” Sinise said during a break while filming HBO’s “Truman” in Kansas City, Mo. “Basically, we formed a collective. We wanted an actor’s theater where we could all do the most interesting things we could find. It didn’t matter if the plays were very good, as long as the roles were.” In search of a name, someone glanced at a book one of the cast members was reading. It was “Steppenwolf.”

Metcalf was there at the base ment beginning of an ensemble that would become one of the most prestigious in the country; it included Oscar nominees John Malkovich (“In the Line of Fire,” “Places in the Heart”) and Sinise (“Forrest Gump”), and Jeff Perry, whom Metcalf married. (Now divorced, they have an 11-year-old girl, Zoe. She also has an 11-month- old boy, Will, by her current companion, actor Matt Roth.)

“It was like ‘Peyton Place,’ ” Metcalf recalls bemusedly. “We were left alone for 10 years. We were free to do anything. You could get naked. You gave everything, even in roles you had no business doing. I played a 12-year-old in ‘The 5th of July.’ I played the mom in ‘True West,’ which I still couldn’t play.”

“From the beginning, you could see that Laurie didn’t have to say a lot to get her meaning across,” Sinise said. “She had great natural ability. Her work seemed effortless. She had an uninhibited quality, yet she was very simple, very clear.”

Steppenwolf gained national attention with a 1982 production of “True West,” the Sam Shepard play. The inevitable pressures of success began to pull the group apart as individual careers began to take off. Metcalf’s performance two years later in “Balm in Gilead” was the talk of New York’s theater cognoscenti. (“The reports on that performance are legion,” Goodman says. “A lot of my friends told me about it.”) It led to roles in two Susan Seidelman movies: “Desperately Seeking Susan” and “Making Mr. Right.”

She also played a lesbian cop in “Internal Affairs.” On the drive to rehearsal after lunch, she looked out the car window and remembered with some amusement a scene in which Andy Garcia’s eyes follow a pretty woman in the street. “I watched her too.”

Of “My Thing of Love” she says: “I play a frustrated housewife who’s intelligent and uses sarcasm to get around the walls she’s put up. She has a hard time being vulnerable. She’s in a box of her own making and doesn’t know how to get out. It’s written in a way--pedestrian? Is that a good word? Yet remarkable things happen that are right out of classical tragedy. It’s shocking what people will resort to in extreme situations. And I like that within the lines there are a million ways to play around with meaning. This character covers a lot of ground.”

Metcalf invited the reporter to sit in on rehearsal; her reasoning was clear in a flash. It’s one thing to talk a game and another to play it. Her scene started with the morning she discovers her husband and his mistress in bed. Metcalf waits for them to wake, and in that moment and in the ensuing dialogue, you saw her snap into focus and understood what her peers mean in describing her. She was vivid. She brought a complex of emotions up to a clear, controlled surface. She was passionately alive.