LA JOLLA--It's nearly midnight when Neil Patrick Harris sits down to dinner in an upscale Italian restaurant not far from the La Jolla Playhouse, where he has just finished a performance of "Rent."

In the hit musical, the 24-year-old actor--better known as the title character in the 1989-93 ABC television series "Doogie Howser, M.D."--plays the lead role of Mark, an introverted aspiring filmmaker who narrates the goings-on among his fellow East Village bohemians.

Doogie still dogs Harris, as the whispers of recognition that ripple through the theater audience attest. But with his black nail polish and cultivated angst, Harris' Mark is a long way from the kid doctor he used to play.

According to the seasoned yet congenial Harris, Mark's detached attitude is actually a lot closer to his own.

"I'm very much like him," says the actor, as a waiter sets a bowl of pasta and a glass of wine in front of him. "I'm very analytical, so it's hard for me to just be present to whatever emotion is going on in a moment without thinking, 'What does that mean?' "

"Neil has that wonderful combination of heart and head that is always a tricky balance with Mark," says Michael Greif, the director of "Rent" and artistic director at La Jolla. "He has that tension between being a guy who's very on top of it and someone who's always looking and analyzing. Neil is smart at seeing that he's not getting away with anything facile. His intelligence comes through keenly."

Harris also understands a dilemma his character faces:

"I respect his struggle with 'Do I sell out and do a cheesy TV show, or do I wait and maybe be poor and do what I want to do?' "

Not surprisingly, Harris faced a similar decision after the end of "Doogie."

"I did a TV show that was very good and my TV-Q was very high," he says, referring to the index of a performer's recognizability and popularity. "I had the opportunity then to do more TV and make a lot more money. I didn't want to do that, and I'm glad I didn't."

Harris chose instead to make his own way with a career path that has included films, TV movies and, more recently, theater projects. And now the strategy appears to be paying off.

In addition to "Rent"--which will move to the Ahmanson Theatre in Los Angeles late next month--he also has two films coming out in the near future: Paul Verhoeven's sci-fi epic "Starship Troopers" and the 1930s period drama "Shakespeare's Sister," with Kenneth Branagh and William Hurt.

The latter film, in which the actor plays a young man hired by a wealthy couple to sire their child, may well be a breakthrough for Harris.

"He's quite an amazing actor," says director Lesli Linka Glatter. "He is funny and moving at the same time. The character is written much as an innocent, yet he's top in his class at Harvard Law. He just understood who the character was and ought to be. He made it very real and understandable."

One reason Harris may have had such good instincts about his "Shakespeare's Sister" character is that he comes from a long line of lawyers, including his parents. He has an older brother, Chris, who is currently in law school.

Harris is of Scottish, Irish and English descent--"I couldn't be whiter," he quips--and grew up in Ruidoso, N.M. His got his first taste of live theater as a child, when he caught a road company of "Annie" that passed through Albuquerque.

He first tried the stage himself when he attended a performing arts camp at the University of New Mexico.

"It was awesome," Harris recalls. "I'd never done anything like that before."

After that, he began to work in community theater. Meanwhile, the idea of a career in entertainment grew on him.

Harris broke into movies at the age of 14, starring opposite Whoopi Goldberg in the 1988 film "Clara's Heart." Not long after that, he was tapped to play the title character, a prodigy who graduated from medical school at 16, in Steven Bochco's "Doogie Howser, M.D."

Almost immediately, it proved to be a different sort of challenge.

"On the TV show, we had a lot of work to do in one day's time, so it was much more technical," he says. "It's not about figuring out the character. It's 'We have an hour, so you need to stand here.' "

Even more difficult, perhaps, was that Harris spent his teen years in the public eye.

"I sort of went through puberty on the show," he says. "Then, by the time I was making my own decisions, I was being watched."

"I don't know if it was fate or what, but all these things happened to me that you would have to say yes to. When I was in high school, they came along [and said], 'Do you want to star in a movie opposite Whoopi Goldberg?' What are you going to say? Then it was 'Do you want to spend four weeks in Big Bear [making a TV movie] and make $100,000?' So I never even thought about law as an option." ,p> He doesn't have serious misgivings--"the benefits outweigh the drawbacks"--although Harris is aware of having skipped a phase in his social development by not having gone to college:

"There's a strange reverence because of my celebrity that prohibits pure anonymity: mindless socializing and frat parties, getting drunk and just sleeping around. I do think everyone should have the chance to be thoroughly unknown and an adult and just go off if they want."

In lieu of such pursuits, Harris became a theater fan, taking frequent trips to New York to see the major plays and musicals.

"I had the money, because of the series, to be able to go to New York when I wanted to," he says. "I think if you can, it's really good culturally to see people live. It makes a deeper impression than going to the movies."

Even today, he continues to take the trek east two or three times a year "just to catch up." He cites "An Inspector Calls," "City of Angels" and "Into the Woods" as some of his favorite stage productions.

'Rent" was another show that Harris saw in New York. He didn't originally see the musical as a vehicle for his own talents, although he did become a sing-along fan when the cast album CD was released.

"I'm always looking for something I can sing to that I might potentially be able to do," Harris says. "I listened to it all the time for like a year, up until the time that I got [the role], and I just never got tired of it."

Although Harris' work was praised when he played the lead in the Stephen Sondheim-James Lapine comedy "Luck, Pluck and Virtue" at the La Jolla Playhouse in the summer of 1993, and again when the play went to New York in 1995, "Rent" is his first musical.

"I always wanted to do a musical, but I didn't want to do mindless fluff," says Harris, whose other theater credits include Jon Robin Baitz's "The End of the Day" at the Coast Playhouse in Los Angeles in 1994. "It gives the theatrical medium a bad name."

Harris was attracted to "Rent" in part because of its generational appeal.

"It was so nice and refreshing to see people of my age being cool onstage, and [hear] rock songs," he says. "One of the things that I'm really excited about is that my peers, this heroin-chic, 'we're so much cooler than anything' set, might acknowledge that theater is some sort of option. It's trendy, it's emotional, and maybe it'll have some impact."

What Harris likes most is that the show isn't pretty and tidy in the style of a traditional Broadway musical.

" 'Rent' is from the beginning like a rock concert," he says. "You see the mikes. So when we do come out and stand there and sing, you haven't been under the guise that it's anything but what it is, which is raw and rough and ugly sometimes.

"That allows us to do whatever we want. If I'm really upset and emotional at a show, I can use that. And if I'm quiet and introspective, I can use that. You don't have to put on a happy face every night."

Apparently, it's a setup that suits Harris. Times theater critic Laurie Winer called his performance in the Jonathan Larson work "a mighty stroke of good casting," adding: "Harris not only has a winsome voice, he's lanky and light on his feet, with just the right mix of irony and sweetness."

That mix is also the formula that Harris makes work in "Shakespeare's Sister." The "intelligent potboiler," as director Glatter calls her film, is set in 1935 and concerns a wealthy but childless couple (Hurt and Madeleine Stowe) who decide to hire a sexual surrogate (Harris) to impregnate the wife. The story is narrated from the perspective of a priest (Branagh) who watches as the situation spins out of control.

"There's definitely a dark comedic part to it, so [the task was] to find someone who embodies that American optimism yet with a certain sense of innocence," Glatter says. "You feel a lot of compassion for the character. I think he felt a lot of compassion for the character."

Less dramatically demanding is Harris' role in the big-budget sci-fi film "Starship Troopers," due out in November.

"I'm the super-intelligent best friend with psychic ability to speak to animals," he says. "I come in after the battles and touch the bugs and say, 'They're afraid!' and everyone cheers.

"With 'Starship Troopers,' when I was looking at some bug, you knew it was going to be a really cool, legitimate bug, not some B-movie bug. I don't want to see that. I'm a perfectionist. I want things to be done as best they can."

Harris, whose hobby is magic, cites as his favorite theater artists those whose work either requires or contains a certain amount of creative decoding, such as David Mamet or Rupert Holmes.

"I have a very games-puzzle mentality," the actor says. "I like to be able to figure things out. I respect Shakespeare in that way, though I haven't studied it at all. I respect that in there is an answer."

The problem, he says, is that most of the theater he finds in his adopted hometown of L.A. is anything but creatively complex.

"I'm frustrated with theater in L.A. because most of what I pay $12 or $15 to see is not a show but a showcase some actor wants to do to get casting directors to see him," Harris says.

"It just frustrates me because I like theater in New York so much. Even off-off-off-Broadway, they care about the show and they're there to learn."

Still, he sees himself continuing to balance projects in film and theater.

"The thing about theater is the older you get, the more roles are accessible to you," Harris says. "At 21 or 22, or even at 24, you have very few role opportunities. Theater mostly comes when you're 28 or early 30s, when you can play a definite leading man."

Beyond those roles yet to come his way, he has other aspirations.

"I'd really like to start directing, but I'm only 24 and I just don't think I'll be taken seriously yet," Harris says, referring to both film and theater. "Otherwise, you're just a flash in the pan, and I don't want to be that."

"Rent," La Jolla Playhouse, UC San Diego campus, La Jolla. Tuesdays to Saturdays, 8 p.m.; Saturdays and Sundays, 2 p.m.; Sundays, 7 p.m. Ends Sept. 14. $30-$65. (619) 550-1010. Also Sept. 28 to Jan. 18 at the Ahmanson Theatre, 135 N. Grand Ave., downtown. $32-$70. (213) 628-2772.

Jan Breslauer, THEATER; The Post-Whiz Kid Phase; Neil Patrick Harris is best known for playing the teenage doctor on TV's 'Doogie Howser, M.D.' But with roles in 'Rent' and two new films, his career as a grown-up is. , Los Angeles Times, 08-31-1997