Her credits as a movie star ("Fried Green Tomatoes," "Longtime Companion," "Bullets Over Broadway") notwithstanding, Mary-Louise Parker can probably take the most pride in her theatre work. Not only does she return at least once a season to the New York boards -- and usually Off-Broadway at that -- her choices have proved impeccable. Recent years have seen her as Li'l Bit, in Paula Vogel's Pulitzer-winning How I Learned to Drive; the tough-but-innocent Poopay in Alan Ayckbourn's Communicating Doors; and, currently, the heartbroken and possibly unbalanced daughter of a mentally ill physicist in David Auburn's Proof, for which Parker has received the most glowing notices of her career. The show has extended until at least July 30. No word on what happens after that (there's talk of Broadway), though Parker told Playbill On-Line she'll be in David Leveaux's Roundabout revival of Desire Under the Elms this fall. Of course, theatre was the springboard for Parker's ascent; she was a Tony nominee and Derwent Award winner for Prelude to a Kiss, and she later returned to Broadway in a 1996 revival of Bus Stop opposite Billy Crudup. But her continued commitment to live drama is admirable nonetheless.

There's a handful of young performers—Matthew Broderick, Cynthia Nixon, Robert Sean Leonard, Calista Flockhart, you—who make it their business to stick with the theatre. Why do you do it?
Mary-Louise Parker: When a play comes along, I often have to turn down other things that would allow me to make money. Sometimes I'll pick something beforehand that will allow me to do theatre for awhile. I'm pretty conservative with money; I could do theatre and not do other stuff for awhile, but you have to map out a career. It's hard if someone's offering you a lot of money or a great location. In the case of Proof, the play I'm doing now, I can't imagine anything giving me what this play has given me. No movie could ever do that.

Did you know early on how strong a hold acting and the theatre had on you?
MLP: It was not a cerebral decision, not something I examined. It was visceral, instinctual. I just found myself doing it. I'd gone to professional arts school [North Carolina School of the Arts] and had already decided what I wanted to be before I went to school. The day I graduated, I moved to New York City. I had no plan, but it just happened naturally. I didn't work for awhile; I sold shoes, worked telephone jobs -- whatever I could. I got my first job a few months in, doing Night of the Iguana at the Hartman Theatre in Stamford, CT. At the same time, even when I got Prelude to a Kiss, I was so unbelievably naive. I didn't know what a Hirschfeld was until I got one. I didn't know who Frank Rich was. I was either doing a play in Central Park with my friends or somewhere with boys. I was boy-crazy, too, so it was all boys and theatre. Now, I knew people who read Backstage and went to every play, but I never did any of that. Eventually Peter Hedges, Joe Mantello, K. Todd Freeman and I started a theatre company, the Edge Theatre. But the business side went completely over my head. Even now I don't read the paper or watch TV. Not that I think I'm above it by any means. It's just not habitual by me. Instead, I get an entire education every time I do a new play. I learn by doing.

Any exceptional influences on you?
MLP: Well, the directors -- Norman Rene, Dan Sullivan, Mark Brokaw. Playwrights Craig Lucas, John Patrick Shanley, Paula Vogel, Terrence McNally -- (I did his Up in Saratoga) -- Alan Ayckbourn. That's where I feel unbelievably blessed. You get directors and writers like that, you have to get down and kiss the ground. Norman Rene was so brilliant. And it was in what he didn't say. He was about unbelievable restraint. He really showed me the importance of not making the moment about you and your acting, but about the play, the text, and how delicate it is. That was the cement foundation. Actors think any laugh is a good laugh, any emotion is a good emotion. But it can't be about your laugh, emotion and moment. They're wonderful and really important, but they can't be more important than the play. That's something always to remind yourself of -- even if you can't make it all the time; it's something to aspire to.

It might be said that the last several stage characters you've played have all had a common thread: they've all been deeply wounded yet cover that with a surface resilience. Do you detect a pattern here, or do you not even see a connection at all?
MLP: I see no connection between them. I do try to play people with a strong emotional life, and everyone's wounded to some degree. But I went into these plays because they speak to me, and because I thought the writing was really excellent. People want to draw conclusions about things and create a familiarity. But where's the connection with Four Dogs and a Bone or The Art of Success? They've all been very different to me. Granted, there's a kind of writing that I'm attracted to. It involves people being defined by what they reveal and don't reveal at any given time. In How I Learned to Drive, the character wasn't willing to reveal anything. She simply told the story in a very direct and positive and emotionless way. She let you in to see certain events in her life. But this was presented with impartiality, even as the content of the scenes was specific and emotional. This character is extremely withholding in a situation where she's constantly being pushed. In Proof, I don't think Catherine is an incredibly strong person... yet I don't think she'll go the way of her dad. That's my opinion. Certain things are from genetics and unavoidable, but it's how they're dealt with and approached and faced. I think she stands a good chance to be all right.

Not to get morbid, but have you undergone a period mourning similar to Catherine's?
MLP: Few people in my family have died. I lost Norman Rene, who was extremely close to me. But even so, I don't draw on my own stuff really. You can personalize them to a degree and filter them, you have to because you're playing the character. But to personalize would make it about my life, and this is a completely different situation.

You'll be doing O'Neill in a couple of months. Any thoughts on other classic works you might hope to tackle in the future?
MLP: Some roles I wanted to play have passed me, such as Nina in The Seagull. I love Tennessee Williams, but I never got to do Laura [in The Glass Menagerie]. I also love Noel Coward and Oscar Wilde. And maybe one day I'll do Cat on a Hot Tin Roof -- my first professional job was Night of the Iguana. At the same time, I don't like Moliere. I didn't like the restraint the meter puts on me. Doing it made me feel like I was in jail. I appreciate Shakespeare but I don't respond to it, in terms of wanting to do it. I've seen him done well twice, and it knocked me on my back. But most of the time I don't know if I'm quite vigilant enough to follow it. I start to space out. Really, I'm so passionate about new plays; I love reading something brand new, and the magic of that. I love what's undiscovered. I wanna see what [Jon] Robbie Baitz and Craig Lucas will write next. I'm dying to see what David [Auburn] will write next.

Do you remember the first show you ever saw that made a real impression on you?
MLP: I remember in my first year of drama school seeing the senior class doing The Homecoming. Joe Mantello was playing the father, and he completely blew my mind. I saw acting in a different way. I saw what he'd done with these pages of words. To be around people that did that. He was astounding. He blew me away that day.

But that was already when you'd long made up your mind to be an actor. How'd you get hooked?
MLP: Performance was the only thing I was good at. I was really quiet, shy and stuttered. They put me in dance class when I was four. I was shy, but I was the only one who wasn't afraid to go onstage. I had an older sister who was an actress who I idolized. She did it, and I worshiped her. She was really talented and funny, and also very pretty. It was hard for people to take her work seriously because she was so pretty. She doesn't act anymore. But in my case it was more like, "Why is this child unable to speak to you or look you in the face but ready to go out there and do this tap dance and not even blink about it?" There's a part of me that's still not comfortable in large groups of people. I'm just not very social. I was when I was younger. I was pretty outrageous then, even something of an exhibitionist. I was slightly out of my mind. Adam Duritz, my friend [lead singer songwriter of the Counting Crows], once told me that it's not stage fright but life fright. I can say that with a sense of humor, but even now, I'm pretty happy on stage, and much happier there than I am at the party afterwards.