Johnny Depp: His performance in Sweeney Todd has been acclaimed as 'stunning in every dimension'

"Idiot," Johnny Depp likes to joke, is the German translation of his surname. The universally swooned-over film actor, who this week picked up his first Golden Globe for his all-singing portrayal of Sweeney Todd, has, over a 24-year career, gained a reputation for playing the outsiders, rejects and oddballs – the idiots. Big-bucks, twinkly-eyed romantic leads – for which his unimprovable looks might seem to make him an obvious contender – have never held any allure.

Instead, Depp has transmogrified into pallid Edward Scissorhands, kohl-eyed pirate Captain Jack Sparrow and Cry-Baby Walker, the delinquent of John Waters' 1990 film. He has crossed-dressed in both Before Night Falls and Ed Wood, shaving his legs for the latter. "I always thought it would be interesting to see them all in the same room together," Depp says of his characters.

Tim Burton, who has directed Depp six times, describes the actor as a risk-taker. "He could have gone and made millions of dollars as this great-looking lead guy. But no." Depp turned down leads in Speed and Interview With A Vampire, but he's not in penury: he picked up $20m for each his Pirates Of The Caribbean films, and smaller movies reputedly start at $8m.

With that straggly beard, skull rings, nerd specs, fedora, leather jackets or Rat Pack suits, Depp doesn't have the clean-cut appeal of a Pitt or a Cruise. His is "a delicate beauty that's startling, perhaps more so for being intermittent ... with a tilt of the head, impossibly handsome," according to Franz Lidz in the New York Times. On celluloid, Depp does not exude menace or muscularity but rather a lightness and naturalness. "Johnny doesn't rely on tricks, his acting is about ease and intuition," says Lasse Hallström, who directed him in both Chocolat and What's Eating Gilbert Grape?.

Following the success of the Pirates films, Depp is now in the enviable position of being a blue-chip Hollywood name with indie appeal. He doesn't play the La-La land games – no Scientology training videos here – and claims not to have seen the final version of many of his films: "Once my job is done, it's none of my business. I walk away."

Timothy Leary has described Depp as a contradictory mix of "wild and charitable". Following the treatment at Great Ormond Street of his daughter Lily-Rose for an e-coli bug last year, Depp donated £1m and then returned, dressed as Captain Sparrow, to read stories to its patients at Christmas. In 2007, he was voted "best signer" by Autograph Collector for the third year in a row.

Born John Christopher Depp III on 9 June 1963 in Owensboro, Kentucky, he is the youngest of four children – today his sister is his personal manager. At the age of eight, his father John, a civil engineer, moved the family to Miramar, Florida. The Depp clan moved 30 times before he turned 15. His father and mother, Betty Sue (whose name is inked on his body), fought and eventually divorced. Taking up smoking at 12, he still puffs on roll-ups – and losing his virginity at 13, Depp then "did every kind of drug there was by 14". Locking himself in his room, he learned guitar.

In 1983, Depp escaped to LA and joined the Loft Studio school to take acting lessons, but dropped out to concentrate on his band, The Kids. By this time, he had also acquired a wife, Lori Allison, the sister of one of his bandmates. The Kids were successful enough to support Talking Heads and the B-52s but Depp was still forced to find sales work. "We sold ink pens. I had met Nicolas Cage who was, like, a friend of a couple of friends. And Nick told me one day, 'You should try acting or whatever'."

Depp went to see Cage's agent and in 1984 landed his first significant role, in Wes Craven's Nightmare On Elm Street. Depp played a boy who gets swallowed by a bed, and he made $1,200 a week. That was followed in 1986 by a small role as a Vietnamese-speaking private in Platoon. But television gave Depp his breakout role, as an undercover cop at a high school in the Fox drama 21 Jump Street. He received 10,000 fan letters a month and simpered on the covers of supermarket magazines. He hated it. "I didn't want to be, you know, saccharin bon-bon," he has said.

The teen idol image was all but forgotten after his first movie with Tim Burton, where Depp played Edward Scissorhands. For two hours a day, over four months, Depp was made up with thick white face paint and fake scars and, for 45 minutes, sewn into his black leather body suit. Another hour was spent on his wild black shock of hair. "Everything needed to be said with the body or the eyes," says Depp, who based his characterisation on "a newborn baby and the dog I had when I was a kid".

But, even as Depp chalked up critically-acclaimed roles in Gilbert Grape and Benny & Joon, he took more drugs. "It was anything I could stuff into my system to medicate, self-medicate, or numb myself," he admits.

The role of Ed Wood, sometimes called the "worst director of all time" and another Burton project, was for Depp "the rocket ship that took me away from that horrible black bleak time". So convincing was his female impersonation, Depp was reportedly considered as the first transvestite cover girl of US Vogue, a proposal that was sadly nixed.

During the late 1990s, he starred in Don Juan DeMarco, Donnie Brasco, Fear And Loathing In Las Vegas, Sleepy Hollow and Chocolat. In 2001, he played the 1970s cocaine kingpin George Jung. Then came a curious career transition . From that seedy role, Depp moved into the world of Disney family movie fun, starring as Jack Sparrow in the first Pirates movie in 2003. Depp has since said he felt he could"infiltrate the enemy camp". More than that, fatherhood had altered his tastes. "I thought it would be great to make a movie that my kids could watch."

Meanwhile, Sweeney Todd, which opens in British cinemas next week, has been hailed as the Burton-Depp relationship at its best, the New York Times gurgling that "his performance as captured on screen is stunning in every dimension." Even Depp's singing has mostly been praised; only the New Yorker's Anthony Lane dismissed his warblings as a "Bowie impression". That's an improvement on Lane's verdict on 2005's Charlie And The Chocolate Factory, where he called Depp's Wonka "an ageless weirdo" who smiled like Michael Jackson.

Meanwhile, Depp himself cited Keith Richards as the equally unlikely reference for Captain Sparrow's strung-out shtick. He has never done any stage work. When reading a script for the first time, Depp says he "gets flashes of images" that suggest a character. Although in his youth he did read On Method Acting, he has said that No Acting Please by Eric Morris and Joan Hotchkis was the more influential text. "I was never one of those guys who ever believed [...]you become the character and, you know, when you walk to the coffee machine, you are Henry VIII."

If there is criticism of Depp's work as an actor, it is that his weirdos are so emotionally guarded that we never get beneath their skin. "I respect Johnny's instincts. For me, however, it seems he's been hiding a bit beneath eccentrics and outcasts," says Hallström.

In the 1990s, Depp's personal life was as tempestuous as any of his characters'. He had a bad-boy reputation but says "they pinned that on me". The drugs probably weren't a good idea, but the other misdemeanours were minor. He and Cage used to hang by their fingertips from a fifth-storey garage for kicks; he checked into hotels under the names "Mr Donkey Penis" or "Mr Stench". It didn't make Depp look good when, in 1993, his friend River Phoenix died at the Viper Room, a club on LA's Sunset Strip that he co-owned. His self-harming, meanwhile, is well-documented – there is a cut in his arm for every "important event" of his life.

And then there are the women. Over the years engaged to the actresses Sherilyn Fenn, Jennifer Grey and Winona Ryder, Depp has been given to extravagant declarations, and then retractions, of love. At the end of his three-year relationship with Ryder, he famously altered his "Winona Forever" tattoo to read "Wino Forever".

In 1994, he had an affair with Kate Moss. He gave her diamonds; she gave him a ring-shaped platinum rattle filled with black pearls. But they also had public spats. After a row with the model, he trashed a room at the fancy Mark Hotel in New York, causing $10,000 of damage, and spent time in a cell. That night Marlon Brando, whom he befriended on the set of Don Juan DeMarco, called Depp's lawyer to offer "if there was anything he could do to help". Perhaps when Brando wants to help out it's a sign that things have gotten out of hand.

Many credit his calmer ways with meeting the French singer Vanessa Paradis. They flit between St Tropez, the Hollywood Hills and the Bahamas. Lily-Rose was born in 1999 and a son, John "Jack" Christopher was born in 2002. Depp first saw Paradis in a Paris restaurant in 1998. "I saw this back and this neck. I thought, my God, what's that? And it made eye contact. I was done." She says her body tingled when she shook hands and admits that "half the world would like to be with my boyfriend".

For all his rebellious instincts, Depp is uncomfortable with political statement. In 2003, he tried to withdraw quotes that criticised the Iraq war – dismissing America as "a dumb puppy that has big teeth" – given to Stern magazine in 2003.

Perhaps that attitude will have to change: Depp's production company has bought the rights to the story of the Litvinenko poisoning. If all else fails, he's kept the scissorhand gloves. "In a couple of years, I may be doing birthday parties at McDonald's – as Edward. You know, $200 a party." An idiot? Hardly.

A Life in Brief

Born: June 9 1963, in Owensboro, Kentucky, US.

Education: Left school at 16.

Career: Tried to forge a career as a rock musician before turning to acting. His first leading role was in Tim Burton's Edward Scissorhands in 1990. He has since collaborated with Burton on numerous projects, most recently Sweeney Todd: The Demon Barber Of Fleet Street, for which Depp received a Golden Globe. He has twice been nominated for the best actor Oscar – for his portrayals of Jack Sparrow in Pirates Of The Caribbean and JM Barrie in Finding Neverland. The final instalment of the Pirates trilogy is the third-highest grossing film of all time.

Family: Two children, Lily-Rose and Jack, with his partner, the French actress and singer Vanessa Paradis.

He says: "I was given the 'weird' badge but I think everybody's weird and that's the key to it. We should celebrate our individuality, not be embarrassed or ashamed of it."

They Say: "I like actors who don't look at themselves all the time, on a monitor after takes. Johnny's one of them. I'm not sure he's seen any of the movies we've made together." Tim Burton, writer and director