Liam Neeson - an Irishman in New York

The Irish actor Liam Neeson is bewildered. He has just finished performing Samuel Beckett's play Eh Joe at the Lincoln Center in New York, not far from where he lives. Theatrically, it's the Olympics of performances. For 30 minutes Neeson sits on a bed, while a woman's voiceover carves up his psyche. Neeson doesn't say a word. Using no more than facial expression, he is mentally devoured on stage as the audience watches, spellbound. Atom Egoyan (the acclaimed Canadian director of The Sweet Hereafter), who directs, describes the role as "the longest reaction shot that an actor can imagine".

Neeson is bewildered because, "I got a review in The New York Times and, God, it's the best review I've ever got in 33 years," says the actor.

No one else is surprised. Twenty-one years ago the Irish lad with the movie-star good looks played a homeless mute on trial for murder in Suspect. Without dialogue, he still managed to upstage Hollywood stars Cher and Dennis Quaid. It was a turning point. He followed that up with more beautifully nuanced characterisations, such as the down-on-his-luck private eye in Under Suspicion, and the compassionate doctor in Nell. There were duds along the way (remember the remake of The Haunting?), but Neeson has always been at his best playing real-life historical figures. Schindler's List earned him an Oscar, Bafta and Golden Globe nomination in 1994; Rob Roy (1995), Michael Collins (1996) and Kinsey (2005) added to the esteem in which he was held.

"I've never set out to play real people," he says. "But I suppose the appeal for me is that we live in such a corporate world that the buck is continually being passed. Rarely do our elected leaders say, 'you know something, this is all my fault and I'm going to do something about it.' I respect people who do that and I'm drawn to those people who stand up for something."

Taken, his latest film, is something of a departure. In the film, directed by Pierre Morel (District B13), Neeson stars as the ex-government operative Bryan Mills, who ruthlessly hunts down an organised gang of sex-slave traders who have abducted his daughter (Lost's Maggie Grace). It's a brilliant piece of casting, because Neeson's quiet gravity makes for an unconventional annihilator.

"I'm always motivated by script first," he says. "And it's either something that gets under my skin or it doesn't and I did love the action of this one. I've done a few of what I could call 'cowboy-in-armour' films. It's play-acting with shields and spears and it's like being a kid again. I also loved the fact that I was being asked to do it. I was 54 [now 56], and I thought, 'in a few years' time I'm never going to be asked to do this sort of stuff again'."

He missed that on Narnia, in which he voiced the part of the lion, Aslan. His contribution involved "going into a studio for a few hours," he says. But, he adds, "there's a huge part of me that would have loved to have been on set with those kids because I love the physicality of making films."

Neeson is in amazing shape. Just last year he was voted "the ideal Irish bed partner", beating out Colin Farrell and Jonathan Rhys Meyers, much to his embarrassment. But this physical prowess was important because Morel expected him to perform the majority of his own stunts. It took weeks of rigorous training to master the complex martial art called parkour, a propulsive fighting style, which is a major part of the movie.

As for mental preparation, Neeson's process is not to have a process. "I've learnt over the years not to over-think things. For me it's an instinctive thing and the more I try to intellectualise the process the more I can mess it up," he laughs.

"What I did find interesting territory on this one, however, is the violence. I'm a father, I've got two sons and you wonder what your own reaction would be if your child was taken. You soon come to the conclusion that you'd do anything in your power to save your child."

Neeson has thought about revenge a lot. Not of exacting it himself, as he's "traditionally against violence", he says, but rather the motivations behind it.

"I grew up amongst the Troubles in Northern Ireland. I was surrounded by violence and bitterness and the desire for revenge. Bryan's thinking is 'it's them or me', and I certainly knew lads who thought like that. But that idea is anathema to me and I couldn't wait to get out of it."

Neeson is wary of talking about Ireland. A few years ago he caused a furore when he told a US magazine that, as a Catholic in a predominantly Protestant town, he grew up feeling like a "second-class citizen".

"That was a bit rash," he says now. "The trouble with Northern Ireland is that you're cursed if you speak and you're cursed if you don't – at least you are in my position."

He boxed as a young man, then switched to a teacher-training course looking for his ticket out. He was "useless" at teaching, and, on a whim, he auditioned at a theatre in Belfast. Two years later he joined the Abbey Theatre in Dublin. That's where John Boorman spotted him. The director needed a tall actor for his upcoming film Excalibur (1981). Neeson is 6ft 4in.

It was where he met Helen Mirren, the first of several high-profile women he has dated, including Brooke Shields, Barbra Streisand and Julia Roberts. He moved to London to be with Mirren, but Hollywood beckoned and Neeson relocated there in the middle of the Eighties.

But his breakthrough came through theatre. In 1990 he joined Natasha Richardson in Anna Christie on Broadway. He was spotted by Steven Spielberg (who offered him the lead in Schindler's List), won a Tony and got the girl.

Fourteen years later, he and Richardson are still married, so what's his secret? "I'm no expert. But those couples that say: 'oh, we've been married for 20 years and we've never had an argument,' is a load of bollocks," he laughs.

His boys (Michael and Daniel) have not yet "mentioned the 'A' word," he says. "At the moment they're 12 and 13 and they're both very happy with the idea of being sports stars or rock musicians and I'm very happy with that."

A contented tone creeps into that rich, fluid voice of his whenever he mentions his family. "I am content, yes," he says. "When people ask me: 'are you happy?' I always say, 'you know, it's so mercurial, happiness, but contentedness is very, very attainable.'"

Has he attained it professionally as well? "I think so," he says. "I'm less driven than I use to be. Well, I'm not less driven when it comes to the preparation for it. I'm more driven for that but, all the rest of it, the trappings of the movie business, I must admit that the older I get I have very, very little patience with it."

When it all gets too much he does a play. "There is something extraordinary about presenting something to an audience of people and that audience changes every night and it's live and it's never to be repeated and it just taps into something quite mythic," he says.

Right now, however, films are occupying his time. He'll reprise the role of Aslan next year, and, in January, he begins shooting Abraham Lincoln with Spielberg – another one of those historical figures that Neeson does so well.

"He certainly stood for something," says the actor. "He believed in the destiny of democracy, and he was an extraordinarily complex man, of course. These characters usually are; they're not simple people."

'Taken' opens in the UK on 26 September