He had countless fights then, scores upon scores, full-strength melees that boiled out of clubs, a dozen or more guys whaling away. The glamour of brawls had long since worn off, that lightning feeling from his wrist to shoulder when he knocked a kid cold with one shot. Still, as he stands in his splendid yard near the top of Beverly Hills now – a soft moon hovering like a diving bell, the breeze carrying the scent of hibiscus and that other indigenous crop here, newfound wealth – he finds that, looking back, one battle stands out. He was working the door at Tunnel, a ravenous New York club that drew thousands of kids from the 'hood, where he often took on entire crews from the Bronx or Brooklyn. On this night, though, his lone opponent was a kid crazed on PCP. Time and again, he took the kid down with a mammoth hook or cross – and time and again, the kid got up, his eyes like the scope on an Uzi. "He was pure, total rage," he says, "and as strong as a chimp; there were three of us and we couldn't cool him out. Finally, after this goes on for-fucking-ever, we picked his ass up, opened the door, and threw him as far as we could into the street."

If it's odd to be having this conversation in the poshest zip code in America, it seems all the more so given the speaker's occupation: a $10-million-plus-per-picture movie star. But Vin Diesel was an action star even before he started making movies. His life has been one long pitched battle, starting three days after he left the womb in 1967 and his father walked off for good. Every step has been an uphill slog, and even now, on the lawn of his opulent home – a glass-enclosed mansion at his back, a lot full of tank-size trucks, Harleys in the garage, and a high wall of privet to ward off the curious – Diesel talks like a man under siege, trying to hold his ground. Out there, downhill, the enemy still waits.

"I was a bouncer for nine years – it was all I knew how to do – and my training was to not talk loosely, reveal my shit to strangers. That's still my thought process all these years later: Shut your mouth, watch your back, and keep working till your ass falls off."

I had come expecting a war of my own. Diesel, by reputation, can be hell on journalists: peevish, thin-skinned, and grudging with his time. But instead I found him relaxed and personable and eager to chat, particularly when he learned that we'd gone to the same school and grown up a few blocks from each other. Casually dressed in a tight-fitting T-shirt and muddy hiking boots, he at one point showed off the gut he'd gained for a new film, 'Find Me Guilty,' a movie about mobsters on trial.

"I sat in a room for weeks doing nothing," he says, "just eating and becoming my character. For me to go that long without working out, and not having the body that I built my identity around, drove me pretty close to crazy for a while. But it was fun walking around like Ralph fucking Kramden, parading my gut for the cast."

He showed me into his dining room, where the table was piled with work. What registered, besides the panoply of rich-guy gizmos – the huge plasma screen floating on a wall, the concert-quality sound system that hulked in an alcove – was a series of prototype posters and sketches depicting Diesel in ancient armor. In several he is riding an elephant, glowering from his perch, bare-chested.

"Excuse all this; I've got like five projects going now, including 'Hannibal,'" he says. "That's the big one, and I'm trying to do it right, without it costing out at $200 million."

'Hannibal' has been something of a white whale. It was first scheduled to begin shooting in the spring of '03; now Diesel hopes to launch it later this year. He has long been taken with the general from Carthage who, despite stunning victories over mighty Rome to avenge his murdered father, remains a shadowy figure in popular history. "To the extent people remember him, it's as this savage guy, the barbarian who came over the hills," says Diesel. "But he's more interesting than that. He's a warrior who proved the power of a son's love."

And proved it in a certain X Games, out-there way, armoring and riding two-ton elephants and trampling tens of thousands before him. Another hook – both for Diesel and Denzel Washington, who has a competing Hannibal project in start-up – is the matter of the general's race. Thundering into Rome from what is now Tunisia, Hannibal was one of the first great warlords of color – a black, or in any case brown, Alexander. Ethnologists dispute whether he was African or a Semitic tribesman.

Either way, it's perfect for Diesel, who is the world's first bona fide multiculti film star.

"As a kid who grew up checking all 12 boxes on the census form for race, it was very important to me to tell Hannibal's story and get his greatness out there," he says. "Like me, and like a lot of the guys I wind up playing, he was misunderstood from the get-go. That anger and that hunger you get from being typecast is something I really know from the ground up."

Actually, type-uncast seems more to the point. From the age of 18 till he was "discovered" at 30 by Steven Spielberg (he played a soldier in 'Saving Private Ryan'), Diesel hit brick walls wherever he turned, butting up against his skin tone and demeanor. "I was 'too Italian' for gangsta films, 'too black or Latino' for mobster things, and 'too Jewish or Asian' for commercials. Not only was I dealt a short hand for jobs, I didn't even know what cards I was holding, because they changed with every office I walked into. It got so rough that I'd show up angry, like if you said or even thought something bad about me, there was gonna be trouble between us."

Diesel, whose background is, like Hannibal's, debated – "My mother, by herself, is like five nationalities, and my birth father I never even met" – takes his ethnicity dead seriously. It's partly a function of what he's endured, but mostly about servicing his high-yield debt to the man he calls his hero. That would be his stepdad, a black actor and teacher who sacrificed much for his adopted children. "He came on the scene when [twin brother] Paul and I were babies and my mom was really struggling on her own. As big a talent as he was in rep theater, he basically gave up touring to be a hands-on father, to love us like we were his own. It's strictly because of him that I became an actor and pushed through all the bullshit to make it."

Diesel works like a demon and seldom takes vacations, but he uses what little downtime he does have to play hard. "I'll go up to the country in Northern California with some friends and some sick ATVs," he says. "If you see a guy 20 feet off the ground, getting air up over the treetops, it's probably me. I've got the big Yamaha ATV, the new 450, and it sticks the most bananas landings."

Diesel also relishes doing his own stunts, and the greater the risk involved, the better he likes it. "When we were shooting 'xXx,' I was climbing this mountain to a castle outside Prague. It was late at night and the rocks were wet because it had been raining, and I'm going up this face with just a cable and harness attached to some flimsy rigging. At any minute, the thing could've snapped and I'd have plunged straight down the hill, but it was important to do it myself. When I got back to the set, all the guys said I was insane for having thought it, let alone done it."

For Diesel, the leitmotif of struggle invariably comes up, whatever the topic of conversation. Combat mode has been his default setting for as long as he remembers, and even now, as a zillionaire movie star, the shields don't go down easily. "When you're from where I'm from, you learn one of two things real quick: either to fight well, or to talk a lot of smack. Fortunately for me, I guess, I learned to do both, because I definitely had the X on my back."

What made him such a target? "Well, again, the multicultural thing. I looked black, white, Italian, Latino – someone was always pissed at me. And living between the projects and Little Italy, I had to fight punks of all backgrounds. But also, I just had this fire inside, this burning need to prove myself. Maybe it goes back to what my birth father did. I mean, how do you bolt on kids when they're three days old?"

Diesel, who's neither heard from nor sought his birth father since, quickly took to his stepfather's craft, learning to sing and dance at a young age. By the age of seven, he was acting onstage, appearing in productions at Theatre for the New City and dreaming of a life onscreen. Drawing on his love of comic books and the muscle art of Frank Frazetta, he built himself a body in his middle teens, haunting the gyms of Brooklyn and Harlem. By 17, he and his biceps (dubbed the Kryptonics) were working the door at downtown It-clubs like the Roxy and 10-18. As bouncers go, he was a certified star, earning good money, but that didn't serve to temper his pique, which was displayed in nightly brawls with drunken thugs. "My aggression? It was always there, you know, from day one, and for a while that was the perfect job. I was kicking ass on a nightly basis, which helped with the frustration of not landing parts."

Unqualified to do much besides guard an entrance (Diesel had quit college, and never learned to tend bar), he kept showing up at auditions. But this was the mid-'90s, when nobody was sifting call sheets to hire an ethnic enigma. Finally, after a short-lived move to Los Angeles, Diesel was presented with a book by his mother about making one's own film on a shoestring. Scraping together every nickel he had, Diesel wrote and starred in a 20-minute short about the travails of a minority actor. Shot for a total of $3,000, 'Multi-Facial' is a stingingly vivid piece, evoking the despair of a racial outsider and the hoops he's put through. In 1995, it screened at Cannes; eventually Spielberg came across it and reached for the phone.

"I'm going back there this spring for my 10th anniversary," says Diesel. "Ten years in, and still I can't relax; in my mind it's like I'm always starting from scratch. That's why I had to make 'Multi-Facial,' because I had no Marlon Brando or Sidney Poitier to look up to – I was it, the first prototype 'everything.' And also, I felt I owed it to my dad. It was his dream for me to become a great actor, not just an actor of color."

To that end, diesel is now stretching himself, trying satire and genre films. This spring he'll work against blunt-force type in a 'Kindergarten Cop'-like comedy called 'The Pacifier,' playing a Navy SEAL assigned to guard a family of brats. "It's a fish-out-of-water role, and he's very funny in it, mainly because he doesn't force being funny," says director Adam Shankman. "Instead, he does a take on a tough guy trying to cope with a roomful of screaming kids, and is hilarious at it. I think it's going to open up his audience, and layer that hard-ass rep of his with some warmth."

Next off the line is 'Find Me Guilty,' for which Diesel gained 30 pounds and wore a pompadour. It's directed by Sidney Lumet, the man behind 'Dog Day Afternoon,' 'Serpico,' and 'Prince of the City.' So enthusiastic is Diesel about his showy part as the crime boss Jack DiNorscio that he runs off to fetch a reel of dailies from the just-completed shoot. "I could probably go to jail now for showing you this," he cracks as he slots the disc. "But it was just such a dream for me to make the film that I'll give you one small taste."

On the big plasma screen, the camera pans on a morose federal courtroom. A man is holding forth as his own attorney, addressing the jury in the coarse vernacular of a northern New Jersey wise guy. Several seconds pass before it reaches me that the guy giving the speech is Diesel. Fully transformed by the beer gut and wig, he is funny, profane, and frightening at once, in a Paulie Walnuts-meets-Jackie Mason sort of way. It's a powerhouse scene and an anointment moment, a tap on the shoulder from film royalty. (Lumet will be presented this year with an Oscar for lifetime achievement.)

It's also a reminder of who Diesel was before he took the blind alley of pulp films. In 'Saving Private Ryan' and 'Boiler Room,' he was the big-shouldered street guy with the thousand-kilowatt stare and an intensity that backlit the screen. So good was he at embodying menace that you thought you saw traces of the early Brando, or a better-spoken young Stallone. Certainly he was someone to keep an eye on, and you wouldn't have been wrong in supposing that his true gift was playing reality. He took the bait of eight-figure checks for a string of videogames-cum-movies ('A Man Apart,' 'Pitch Black,' 'The Fast and the Furious,' 'xXx'). Yes, one can make a killing that way, but one can also be a washed-up star at 40 – just ask the Van Dammes and Dolph Lundgrens. Not many actors work to a ripe old age uttering lines such as "If I wanted you dead, you'd be dead."

This, then, is a very big year for Diesel. He is battling the first law of showbiz physics, which holds that all things hot must cool. He is also pitted against the Left Coast saw that there are no second acts for action stars. But that's just fine; Diesel loves a good fight, going back to when he was in grade school.

"I had this thing of talking shit to kids who were four years older than me, which is a great way to catch a beating," he says. "But, hey, you take your lumps and learn to keep your mouth shut." If he can notch a couple of new hits and get 'Hannibal' made, he'll shut a lot of other people's mouths this time, including the critics who've needled him.

As we wrap things up, I ask for his take on a reviewer who called his work "caricature." For the first time all night, Diesel flares.

"Really? He said that? But why? What's his angle, that dickless, no-necked –" He stops for a moment and collects himself. "On second thought, no; I won't respond. As someone who worked the door for years, you know not to give out information so people can track you down later. It's basically the same rule in Hollywood: When thousands of motherfuckers roll to your spot, some of them are going to leave angry."