THE RISE OF KING ALFREDO

"When I was younger, I was less open, I think, than I am now," says Al Pacino. "I sort of felt that I didn't want anything to interfere with whatever my train of thought was." That's an understatement. Stories of Pacino's obsessive approach to acting abound: the time when he tried to arrest someone while playing the cop, Frank Serpico; or how he became so enthusiastic about chopping food while playing a cook in Frankie and Johnny that the noise he made drowned out Michelle Pfeiffer's dialogue. Even the late Lee Strasberg, the man behind the Method school of acting, had to tell his star pupil to relax now and again. "Darling, you have to let go sometimes," he would say; but Pacino ignored his guru and continued to rehearse and prepare for his roles as if his life depended on it. It's no surprise that The Loneliness of the Long Distance Runner is one of Pacino's favourite films. And no less than 11 Oscar nominations (eight for Best Actor, three for Best Supporting Actor; he eventually won the Best Actor prize for playing the blind army officer in 1993's Scent of a Woman) indicate that the dedication pays off.

In his latest film, Devil's Advocate, Pacino plays John Milton, the charismatic head of a secretive New York law firm that offers its partners a unique package of benefits in return for their souls. Unsurprisingly, the man who's given life to some of modern cinema's most malevolent characters (think Michael Corleone, or Tony Montana in Scarface), couldn't pass up the opportunity to take on the biggest bad guy of them all, Satan. With a glint in his eye that you can see a mile away, Pacino's devil is like a recalcitrant child who can't stop making mischief. The film is less a modern morality tale than a slice of Grand Guignol, and Pacino has a lot of fun in it.

"Fun" isn't the word normally associated with Al Pacino off-screen. He's notorious for the way he agonises over just about everything, and he's the complete opposite of those actors who spill their life stories the moment the tape recorder hits the table in front of them. This doesn't mean that he is rude or uncooperative: on the contrary, he almost runs into the Manhattan hotel suite we meet in, and smiles throughout the interview. Wearing his trademark black suit - with a red silk tie hanging half-way down his shirt - he manages to be both flamboyant and cautious. And although his hair is flecked with grey, he still looks younger than 57.

The script for Devil's Advocate had been circulating Hollywood for a number of years, and Pacino had turned it down at least three times before. So why take it on now? "As times changed the script became more viable," he explains. "We figured out a way to give it a type of Faustian idea, so it's about temptation and has a bit more humour than it did. We wanted to see if there was anything that would give it a more visceral feeling, an identifiable thing for today's audience, because you're walking that thin line between almost farcical horror and relevant horror. Brecht once said, `If only we could learn to see the horror behind the farce'. He was talking about The Resistible Rise of Arturo Ui, which was his play about a Chicago gangster in the 1930s that parallels his rise with the rise of Hitler. Sometimes humour helps you keep that balance in check."

Back in 1975, Pacino attempted to play Arturo Ui on stage, but the director walked out after Pacino said he wanted more rehearsal time. He's less intense now, but extensive preparation is still a vital part of the Pacino method. "Like all roles that are interesting, you need to research them," he insists. "That's what I like almost as much as anything in acting. It's always a kind of adventure going and finding out things you didn't know before. I'd never read Paradise Lost before, for example. I'm grateful for that alone. Not that I read it all, but I did read a good deal of it."

Making Milton a lawyer was one way of updating the devil for a contemporary audience. "When he says the law is the new priesthood, I guess it's a powerful image. I try and concern myself with creating a character and not the ideas behind the film so much, but it would appear to me that the world we live in is much more litigiously minded than when I was growing up. It seems to be on the front pages and seems to have become part of the fabric of society."

HE WAS Born Alfredo James Pacino in 1940 in east Harlem, New York, and grew up near the Bronx zoo. His parents divorced when he was two and he was mainly raised by his grandparents, who did their best to keep him off the mean streets of the south Bronx. Isolated and unsure of himself, he developed an early love for drinking and smoking dope. Booze and fags would remain a crutch throughout the 1970s and even now, close on 20 years after he gave it all up, Pacino seems to miss them. "I have these sort of health cigarettes. They're herbal and they smell a bit like grass," he says wistfully as he extracts the packet from his pocket. "People think you're really cool after you have one of these, but I'm really not."

At 19, Pacino was hanging out at theatre workshops and leading the life of a Greenwich Village slacker. "In the time I grew up you kind of avoided ambition, it had a pejorative connotation for some reason," he recalls. Neither was it a great time to be ethnic. "We seriously thought of changing our names, because if there was a vowel at the end of it and you wanted to be an actor it was difficult." In 1966, though, after initially being rejected, he got into the Actor's Studio and met Strasberg. Within three years he'd won his first Tony award for Does the Tiger Wear a Necktie? and followed that, in 1971, with his movie debut in Panic in Needle Park. Then, in swift succession, came the films that would make him a star: Serpico, the two Godfathers and Dog Day Afternoon. It's hard to overestimate Pacino's work from that period. As Michael Corleone, his transition from fresh-faced war hero to tyrannical mob boss is so skilfully modulated, it's only when he kills his own brother in the name of the family that we realise what he's become. It's one of the great performances in modern cinema.

Although he's as complex a villain as it's possible to imagine, even Corleone pales in comparison to Lucifer. "With the devil it's different because he's out there, he doesn't have to hide. He wears his evil on his sleeve, he has more relish, whereas Michael was reluctant and had to rationalise what he did." Pacino doesn't seem comfortable when looking back on past work - take his reaction to seeing The Godfather in a cinema for the first time: "I hadn't ever seen it on a big screen, because when it opened I was too nervous, and that was interesting. It was kind of like looking at an old photograph of yourself. You wonder. You just wonder and say, `I can't quite relate'," he chuckles.

Pacino was fortunate that he emerged as a young actor at the same time as American cinema was going through one of its great periods, with directors like Coppola, Scorsese and Altman consistently making innovative and risky films. But he's not prepared openly to condemn 1990s Hollywood and its special effects-dominated movies. "It's not a question of them being less good. I think it's a question of them being different. Somehow journalism, television, the media have taken up a lot of the issues and expressed them, while film is becoming more esoteric and fantastical. When you think of Dog Day Afternoon, that was the first time that you were seeing the media dealing with a real-life situation, where this guy's robbing a bank and it's being televised. Now something like that is run of the mill."

For Pacino, the film industry now appears very much to have taken second place to the theatre, his first love. "I feel as though there's much more I could have done on stage, and consequently how much more I would have been able to develop as an actor. I see so many plays I wish I'd done, because I think it would have been important to me for learning and growth."

A series of high-profile flops in the early 1980s - Cruising, Author! Author! and Revolution - were a painful reminder of that desire, and he took a four-year break from the movies. He also became a father for the first time. Throughout the 1970s and 1980s he dated a string of actresses - Jill Clayburgh, Tuesday Weld, Marthe Keller and Diane Keaton among others - but he's never married, and seems content with his solitary existence in upstate New York. His daughter, Julie, lives with her mother, a New York actress.

During the late 1980s, Pacino also started to make his own films. After the requisite years of painstaking development, he finally made his directorial debut in 1996 with Looking For Richard. A semi-documentary that combined conversations with noted Shakespearean actors and scenes from Richard III, it was part-workshop and part-catharsis for Pacino, who had received the worst reviews of his career when he played Richard on Broadway in 1979. Although he's now working on another project, Chinese Coffee, he won't be directing it. "The level of directing that's out there is so consummate that I do it the way I paint, or sing in the shower," he says with a shrug. "Somebody once asked me, `How come you never played Hamlet?' I don't think I'm particularly right for the part, but I was never asked."

Pacino turns down many more films than he accepts, but promises that there's no danger of him retiring soon. "Someone once said to David Mamet, `David, you write movies, you write plays, you write books, you're constantly writing, how do you do it?' And he said, `It beats thinking.' It's really about engaging in what it is you do. I mean, my grandfather was a plasterer, and the thing about him that I'm left with was his love of what he did. He did that eight hours a day and came home, and you felt that he wanted to get back there and do it again. I remember seeing him in the midst of his work and I saw how focused he was. So I guess it's about having a pursuit and staying with it. What's that saying about he who continues in his folly will one day be wise?"

`Devil's Advocate' (18): nationwide from 16 Jan.