It seems fitting that Andrew Buchan is starring in a play called The Man Who Had All The Luck. Not much more than two years out of Rada, one of Britain's most promising young actors already has a trio of top TV series under his belt, with another, dark thriller, The Fixer, set to fast-track him to stardom.

So, has he really had all the luck? He laughs at the parallel. 'Yes, I suppose on paper I do look fortunate. But what you don't know about is all the stuff I didn't get. It really has been a struggle at times.'

On the day we meet, the just-turned 29-year-old from Bolton is rehearsing the title role in Arthur Miller's The Man Who Had All The Luck, just a week before it opens at the Donmar Warehouse. But that morning he's also been putting final touches to The Fixer, a prime-time ITV1 psychodrama in which he's also the lead. If he's feeling leading-man pressure, then he's not showing it.

The Man Who Had All The Luck was Miller's first Broadway play. It famously flopped when it opened in 1944, running for just four performances. But this fable exposing the dark side of the American Dream has since been successfully revived in New York, with central character David Beeves acclaimed as a worthy addition to Miller's iconic list of flawed American heroes.

A self-taught car mechanic, Beeves enjoys a charmed life in which success, love and happiness seemingly just drop into his lap. But nothing is that easy. 'He's desperate to discover why all this luck has rained down on him,' says Buchan. 'He has to question whether he's really lucky or whether he's made things happen for himself. It really starts to mess with his head.'

It's not hard to see why the play failed. Miller's questioning of God-blessed America was ill-timed: the nation was on the brink of victory in World War II and in no mood to celebrate a character like Beeves, whose crisis of conscience over his fortunate fate sat uneasily with a nation riding the crest of a wave.

Buchan has no doubt over the play's quality. 'With Miller, there's not a word wasted. He packs a powerful punch.'

The role marks Buchan's West End debut, a turnabout from the career path he'd imagined on leaving drama school after completing a degree in Modern Languages at Durham University.

Hamlet featured among his student roles and he's played Mercutio at Manchester's Royal Exchange - I thought that was it, I've done Rada, classical acting here I come!' - but it was TV that claimed him first.

A bit-part detective in ITV two-parter If I Had You was followed by an impressively versatile run as confused cleric St John Rivers in Jane Eyre (BBC1), slick-talking political lobbyist Scott Foster in BBC2's sharp Westminster satire Party Animals and rough-hewn carpenter Jem in BBC1's Cranford.

In The Fixer he plays hitman John Mercer, a buttoned-up soul with a piercing gaze who shoots people for a living. Yet, though Buchan undertook a rigorous training regime to ensure his athletic 6ft 1in frame looked good in a Die Hard vest, The Fixer - by Ben Richards, who also wrote Party Animals - is no brain-dead shoot-em-up. Mercer is a complex character caught up in shadowy intrigue when he's mysteriously released from prison at the behest of Peter Mullan's maverick law enforcer.

Blurring the thin line between good and bad, The Fixer aims to keep the viewer guessing. 'The first killing you don't even see,' says Buchan. 'It's not about blood splatters all over the place, it's not about violence that's in your face - it's much more implied, it's all in your mind.'

Not that The Fixer is without its moments of light relief. Counterpointing Mercer's downbeat intensity is Jody Latham (Lip in Shameless) as Mercer's motormouthing ex-cellmate Callum. There's also a running gag in which Mercer says: 'You'll never see me dance.' It's a sly joke because tucked away on Buchan's CV is a certificate from the Ritmo Tropicale dance school in Ecuador. He can do a mean salsa or merengue if required.

'Spanish was one of my languages at university, so I spent time in Ecuador. And they don't have discotheques, they have salsatheques, so I learned salsa from a little lady who was about the size of Ronnie Corbett - if Dirty Dancing comes calling, I'll be there.'

Then he has to dash back to rehearsals. 'But you're the lead, don't they have to wait for you?' I ask. 'Oh yes, I suppose I am!' He may have had all the luck, but Andrew Buchan is keeping his feet firmly on the ground.

The Man Who Had All The Luck previews from Thu, opens Mar 5, until Apr 5, Donmar Warehouse, 41 Earlham Street WC2, Mon to Sat 7.30pm (Mar 5 7pm), Thu and Sat mats 2.30pm, £7.50 to £29. Tel: 0870 060 6624. www.donmarwarehouse.com Tube: Covent Garden The Fixer is due to start on ITV1 on Mar 10