Following Batman Begins, Murphy stars opposite Rachel McAdams in Wes Craven's Red Eye. Red Eye follows the story of a woman (McAdams) who is held captive on an airplane by a stranger (Murphy) who threatens to kill her father unless she helps him arrange the assassination of a wealthy businessman.

In the fall, Murphy stars as Patrick "Kitten" Brady, a foster kid reborn as a transvestite cabaret singer in 60s/70s London in Neil Jordan's Breakfast on Pluto. Based upon the novel by Patrick McCabe (The Butcher Boy), the film also stars Liam Neeson, Stephen Rea and Brendan Gleeson.

Murphy is currently working on The Wind That Shakes the Barley, directed by Ken Loach. Murphy and Liam Cunningham star as brothers who join the guerilla armies forced to do battle with the British Black and Tan squads trying to block Ireland's bid for independence in 1919.

Murphy's filmography also includes John Crowley's Intermission (2003), a dark comedy in which an ill-timed and poorly executed break-up (initiated by Murphy's character John) sets off a chain of interwoven tales of love and crime. In Peter Webber's Girl With a Pearl Earring, he played Pieter, the local butcher boy who vies for the attention of the title character (Scarlett Johansson).

Other film credits include Anthony Minghella's Cold Mountain, Goran Paskaljevic's How Harry Became a Tree, John Carney's On the Edge, Stephen Bradley's Sweety Barrett, William Boyd's The Trench and Nelson Hume's Sunburn (Galway Film Fleadh).

Murphy first made his mark with a stunning performance in the award-winning stage version of Disco Pigs. After receiving commendations for Best Fringe Show at the 1996 Dublin Theatre Festival and the Fringe First Award at the Edinburgh Festival 1997, Disco Pigs went on to tour extensively in Ireland, the UK, Toronto and Australia. Murphy later starred in the film version directed by Kirsten Sheridan.

On stage, his collaborations with Tony Award-winning director Garry Hyne include The Country Boy, Juno and the Paycock (Johnny Boyle) and most recently Playboy of the Western World (Christy) at the Gaity Theatre in Dublin. Murphy also starred as Konstantin in the Edinburgh Fest production of The Seagull directed by Peter Stein, as Adam in Neil LaBute's The Shape of Things at the Gate Theatre in Dublin and Claudio in Much Ado About Nothing.

His major television credits include the lead role of Paul Montague in David Yeats' BBC television drama The Way We Live Now.

Murphy's short film The Watchmen (written with Paloma Beaza) was short-listed for the Turner Classic Movie Short Film Award.