At 18 years of age he ended up in Wales, doing bit parts in Hamlet; where he became friends with Rhys Ifans (Notting Hill).
When he was on a summer drama course a director from Clwyd Theatr Cymru (The Welsh National Theatre) saw him, liked what he did and asked him to come and work for him.
His parents divorced when he was seven, at which point he was sent to The Dragon School, a boarding school.
He lived in Ibiza for the first seven years of his life.
Played Edward Fletcher-Wooten in the movie The Wedding Date (2005)
At fist he didn't deal with being an actor seriously, because he wanted to work behind the camera.
Played Harris in the movie The Libertine (2004) side by side with his Coupling colleague Richard Coyle, who played Alcock.
Appeared in the adaptation of the Catherine Cookson novel The Moth (1997) as Robert Bradley.
Jack appeared in The pirates of the caribbean (2003) opposite Johnny Depp and will also appear in the two follow-ups Pirates of the Caribbean: Dead Man's Chest (2006) and Pirates of the Caribbean 3 (2007) as Commodore James Norrington.
He is 6' 2" (1.88 m) tall.
Attended Cheltenham College, as did his father, Nigel Davenport.
Graduated in film and English from the University of East Anglia.
His first break happened after he wrote to John Cleese to ask to be a runner on Fierce Creatures (1997) where he ended up playing a zoo keeper.
He was nominated for a 2002 Laurence Olivier Theatre Award for Most Promising Newcomer of 2001 for his performance in The Servant at the Lyric Hammersmith Theatre.
Son of actor Nigel Davenport and actress Maria Aitken.
Jack: Gay nightclubs offer better dance music.
Jack (Jack's advises to London tourists): Go for a walk in Richmond Park and don't buy a doner kebab from a van.
Jack: (About the last time he broke the law) I might have been guilty of doing 32mph in a 30mph zone yesterday. But I can't remember; I was going so fast...
Jack: (About which of the seven deadly sins he would admit to) Sloth. I'm only lazy sometimes, but I berate myself for it.
Jack: (About what makes him cringe) Watching George Bush try to form a coherent sentence.
Jack: (About the Oscars being overrated or not) Not if you're winning one: it'll change your balance sheet forever. If you look at it coldly, of course, to say one film or one performance is better than another then it's a nonsense. But it's the pinnacle of the slightly ludicrous reverence that showbusiness is given in our culture, and very enjoyable for it. I wouldn't refuse one.
Jack (About what's secret of being a happy couple): Compromise. You have to learn to give and take, otherwise you can't share your existance with anyone. You also need to know the correct moment to give gifts.
Jack (About his Coupling character Steve): In many ways Steve doesn't change, but the relationship certainly has. He's still frequently at a loss for words and continues to despair at his own towering ineptitude. He takes a situation, digs himself a big pit of humiliation and shame, climbs into it - and just keeps digging. But he is completely without malice, which is fun to play.
Jack(About "Coupling" being the first time Jack has done several series of anything besides "This life"): It's like putting on an old pair of slippers! We all know how to pace ourselves by now, so enjoy the whole experience hugely.
Jack: During my childhood, I was surrounded by actors and all I remember is they were fun to be around. That kind of sticks.
Jack: Acting is a cruel enough business. One minute everyone's going "Hey!" and the next they're going "Who?". You certainly don't need people knowing your private business, especially if you want to come out with your head still attached.
Jack (About his 'This Life' character, Miles Stewart): A lot of drunken women came up to me in pubs telling me I was a bastard. To begin with I tried to explain that the show wasn't real, but then I found a better tactic was to look them in the eye and say 'Yeah, you know what? I am.'
Jack: People tell me that Hollywood loves new faces, but I don't know. They're probably just being nice.