Even through the fog of a nasty late-winter flu, Joaquin Phoenix remains achingly polite. "Thanks," he says softly when offered a ragged, perforated sheet of Bounty from the kitchen. The 22-year-old actor, who is unavoidably known as brother of the late actor River Phoenix, blows his streaming nose. "Sorry," he apologizes. 

For a performer who has carved out an offbeat movie career playing angry, alienated teens, his off-screen persona is marked more by floor-gazing and foot-shuffling. "I'm just a private person," he admits exhaling a haze of chain-smoked Marlboros. "Sorry." Joaquin was a TV adolescent-for-hire before bursting onto Hollywood screens in 1989 
as Dianne Wiest's sullen teen-age son with a penchant for porno in "Parenthood." 

His next big role came in the form of the memorably menacing Jimmy -- the socially inept slacker with a dangerous crush on Nicole Kidman in Gus Van Sant's 1995 black comedy "To Die For." But between those roles, tragedy brought his private world crashing down on Oct. 31, 1993. As his famous brother, River, lay convulsing from a drug overdose outside a hot Los Angeles club on Sunset Strip called the Viper Room, Joaquin was several yards away pleading for help on a pay telephone. "You must get here, please, you must get here," his anguished brother said, somehow remembering to say "please" and "thank you" to the 911 emergency dispatcher. "I'm thinking he had Valium, or something." River was pronounced dead Halloween morning at Cedars-Sinai Hospital. His surviving brother's private grief is still raw. 
"It's a slow process. I remember thinking as a kid, 'God, what would I do if I lost my dad or mom?' I figured I'd go insane or kill myself," he says. "But somehow, for years, you're so damn out of it. You just sit there." 

Joaquin took a multiyear hiatus from Hollywood. He admits, somewhat sheepishly, that the script for "To Die For" sat unread for many months. "I just wasn't interested," he says. "I just have this tendency to expect the worst from a story. You know, I always see really bad acting, for some reason." Cajoled, he finally picked it up -- and then couldn't put it down. "It was one of those strange experiences where, as I'm reading it, I know what Jimmy's going to say before I read it. The feelings just sort of pop out at me." 
No surprises there -- filmmaker Van Sant's exploration of family relationships has been a special beacon to the Phoenix tribe. River starred in the critically acclaimed "My Own Private Idaho" in 1991 and sister Rain acted in "Even Cowgirls Get the Blues" three years later. Since "To Die For" launched him into the ranks of the up-and-comers, Joaquin has managed to translate his on-screen intensity and brooding looks into more adult roles. 

This month, Phoenix leads some of Hollywood's hottest young stars in director Pat O'Connor's touching Eisenhower-era drama, "Inventing the Abbotts." He joins Billy Crudup as two working-class brothers snared in a complex relationship with three wealthy Midwest sisters, played by Jennifer Connelly, Joanna Going and Liv Tyler. This time, there was no delay getting on board the project. "Some things just touch you, for whatever reason, and this felt so honest to me," he says of the screenplay. "It wasn't trying to be anything that it wasn't."  
Mr. Phoenix and Ms. Tyler -- who since filming ended have been linked romantically -- make a memorable on-screen couple. "I was in awe," he says of his curvaceous co-star. "Every once in a while you find an actor that, with one word, can sum up eight different emotions. She absolutely nailed that." 
The new film also revisits a rich vein of story-telling Mr. Phoenix has previously mined. "I'm definitely a sucker for family movies -- I love those kind of films. I mean, I have no problem with explosions. That's  
all fine and dandy. But generally I like to see real people," he says. 

Born in Puerto Rico, he spent much of his childhood on the move, living in Oregon, Mexico, South America and Florida with his talented siblings -- River, Rain, Liberty and Summer -- while his parents struggled with odd jobs. "When you grow up with a large family," he says, "you have friends right there." One day, while raking leaves with his father, Joaquin decided that he wanted an earthy name like his siblings. His parents 
left the decision up to him. Four-year-old Joaquin temporarily changed it to Leaf. "That's what's so much fun about acting -- being a little kid. It's like playing dress-up. You know, you do a war movie and get to run around in the dirt. I have a blast," he says. But impending stardom hasn't inured Mr. Phoenix to his hardscrabble roots. He recalls the days when all five Phoenix kids were forced to sneak into their tiny apartment, past the "No Kids, No Dogs" signs. "We once got this house on the corner that was the maid's quarters for another house," he says. "But to us, man, it was a mansion." 
"We worked really hard to get to the point where we could own a house, where my dad didn't have to break his back every day," he recalls. "That broke my heart." Acting was a natural escape: "I've always felt when I was younger that there was something missing. I guess you go through  
that growing up -- you want something. As soon as I started working as an actor, I just felt this void had filled." But Joaquin can't quite explain what it is about the Phoenix brood that has produced so much creative talent. "It's a great mystery," he says, smiling. "That's what's so wonderful about it. You just never know. It's this great fear every  
time you go into another movie. It's like, 'Oh my God, what's going to happen?' "And it might leave, too," he warns, not wishing to tempt fate.