Sprawled on the overstuffed sofa in his posh Manhattan hotel suite, the 23-year-old actor looks as though he's already made it. His clothes are expensive Hollywood casual: white Versace shirt, baggy black French pants. A film studio's just flown him east from his home in the Los Angeles hills, where, you guessed it, there's a black BMW parked in the garage. Meanwhile, his manager, Loree Rodkin is padding around in the background, setting up schedules and fielding phone calls. Shoes off and feet up, Downey exudes high spirits, sexual magnetism, and a mocking self-awareness that's as charming as it is surprising. Yeah, definitely star material.

Even without a hit among the 15 movies he's made so far, Downey's career couldn't be hotter. He's now teamed with Kiefer Sutherland in 1969, playing a college student caught up in anti-Vietnam protests, and is about to romance "older woman" Cybill Shepherd in Life After Life. And, he's been offered more roles than he has time for. Critics love him. Touted as a comer in Weird Science and Tuff Turf, Downey won raves as a coke-head in Less than Zero, but the movie got thumbs down. The Pick-Up Artist, in which he co-starred with Molly Ringwald, also fizzled, and two out of three recent projects never got of the ground. None of this seems to have affected Downey. What is it about this guy?

His considerable talent aside, it's probably his attitude. "Because I was born into a creative family, I thought show business would always be part of my life, whether I was involved in it or not," he explains. Son of Robert Downey, Sr., legendary avantgarde director of such off-the-wall '60s classics as Putney Swope and Pound, Downey, Jr., made his film debut at age five in his father's X-rated Greaser's Palace. Being lazy by nature, I chose to be born into a family that would make it easier for me to get involved in acting," Downey says. "I was meant to be in this business." Chose his family? That's right. He means exactly that. "I believe in self-imposed destiny," he states. "Very much so."

He also believes in dumping any pretense in favor of old-fashioned straight talk. On dropping out of Santa Monica High at age 17, Robert says simply, "It was eleventh grade. All I had to do was hang out for one more year. I decided to f--- it. Besides," he admits with a devilish grin, "my dad was moving to New York, and I had to decide whether to hang in L.A. and be independent or stay under my dad's wing for as long as possible and not have to get a job." Did Dad mind? "Please," Downey retorts. "He dropped out in ninth grade - and he's more intelligent than any professor in college. In my opinion.

"Dad's great! He's hilarious," continues Downey, Sr.'s proud progeny. "I've laughed a lot, and I think I've had an accelerated education. It beats school. I couldn't wait to get home from school and start learning." Father and son have worked together on four movies, and Downey, Jr., says he's learned a lot in the process. "In my dad's work, underneath the comedy there was always something poignant. Comedy isn't comedy without something behind it. It's just entertainment without that additional layer." Applying his father's comedic philosophy, Downey played a potentially unsympathetic guy - a nonstop womanizer - in The Pick-Up Artist. Moving from comedy to tragedy in the role of the doomed, bisexual druggie in Less Than Zero was an even bigger risk. Critically, it paid off, however. "Naw, it wasn't scary," shrugs Downey, modestly. "I just figured I'd better get into it and go for it. I tried not to think what an extreme person Julian was."

With that movie, Downey not only received the best reviews of his career, he also added the Jr. to his name. "I'm doing it out of respect for my family," he intones, his accent a fair imitation of Prince Andrew's. Actually, with both Robert Downeys belonging to the Screen Actors Guild, one had to change his name. "I didn't want Dad to think I thought I was so important that he should put a Sr. on the end of his name," explains Jr.

Now that success seems imminent, Downey can reflect a little on what he thinks it means. Suddenly he sounds older than his years, a little jaded even. "What it comes down to in the long run, is that the industry doesn't give a f--- about you," he says. "They give a f--- about how much money you can make at the box office. They don't even really care how talented you are or how much you want to give or how much you love what you do." He accepts all that. "I just say, 'I'm not here to make the movie industry happy, I'm here to grow.'"

Again, his father's influence. Bouncing around the intellectual fringe with the elder Downey (they lived in Woodstock and London, as well as New York and L.A.) gave Downey, Jr. a head start on going against the grain. That precociousness seems to have carried over into his personal life. Filming Firstborn in New York six years ago, Downey met Sarah Jessica Parker and moved in with her a few weeks later. He was 17. "Isn't she sweet?" says Downey of Sarah, who's been credited with having a stabilizing influence on him. They lived together for three years, "and now we don't," he points out. "But I just bought a house and she might move in. If I'm good," he adds impishly.

With Robert Downey, Jr. you can never be quite sure what that means.