Cillian Murphy is an Irish film and theatre actor. He is often noted by critics for his chameleonic performances in diverse roles and distinctive blue eyes.

A native of Cork, Murphy began his performing career as a rock musician. After turning down a record deal, he made his professional acting debut in the play Disco Pigs in 1996. He went on to star in Irish and UK film and stage productions throughout the late 1990s and early 2000s, first coming to international attention in 2003 as the hero in the post-apocalyptic film 28 Days Later.

Murphy's best-known roles are as villains in two 2005 blockbusters: the Scarecrow in the superhero film Batman Begins, and Jackson Rippner in the thriller Red Eye. Next came two contrasting, widely acclaimed starring roles: his Golden Globe Award-nominated performance as transgender outcast "Kitten" in 2005's Breakfast on Pluto and a turn as a 1920s Irish revolutionary in the 2006 Palme d'Or winner, The Wind That Shakes the Barley.

In 2010, Murphy will co-star in Inception, a big budget movie starring Leonardo DiCaprio by Batman Begins/The Dark Knight director Christopher Nolan.

A resident of London since 2001, Murphy often works in or near the city and has expressed no desire to move to Hollywood. Uncomfortable on the celebrity circuit, he customarily gives interviews about his work, but does not appear on television talk shows or discuss details of his private life with the press.

Born in Douglas and raised in Ballintemple, two suburbs of Cork, Cillian Murphy is the eldest of four children. His father, Brendan, works for the Irish Department of Education and his mother is a French teacher. Not only are his parents educators, but his aunts and uncles are also teachers, as was his grandfather. Musicianship also runs in the family, and Murphy started playing music and writing songs at age ten.

In mid-2004, Murphy married his long-time live-in girlfriend, Yvonne McGuinness, an artist whom he met in 1996 at one of his rock band's shows. The couple live in northwest London with their two sons Malachy (born in 2005) and Aaron (born in 2007).

Murphy is known for being reluctant to speak about his personal life. He frequently gives interviews about his work but did not appear on a single live TV chat show, where actors customarily share information about their private lives, until 2010, when he was a guest on The Late Late Show on Ireland's RTÉ to promote Perrier's Bounty. He does not have a stylist or a personal publicist, travels without an entourage, and often attends premieres alone. Shy and private, Murphy professes a lack of interest in the celebrity scene, finding the red carpet experience "a challenge... and not one I want to overcome."
He intentionally practices a lifestyle that will not interest the tabloids: "I haven't created any controversy, I don't sleep around, I don't go and fall down drunk."

Murphy is friends with fellow Irish actors Colin Farrell and Liam Neeson, looking up to the latter like a "surrogate movie dad". But primarily, Murphy's close friendships are those he made before becoming a star.

Music is still an important part of Murphy's life. In 2004, he said, "The only extravagant thing about my lifestyle is my stereo system, buying music and going to gigs." He no longer plays in a rock band, but regularly plays music with friends and on his own, and still writes songs. Unlike many other famous actors who are also musicians, he does not plan to start another band: "Even if I was good, the very notion of being an actor with a rock band on the side would mean I'd never be taken seriously." Murphy is also a dedicated runner.

Though raised Catholic before turning agnostic in his teens, Murphy ultimately became an atheist after researching his role as a nuclear physicist/astronaut in the science fiction film Sunshine. He is a longtime vegetarian, not due to any moral objection to the killing of animals, but because of qualms about unhealthy agribusiness practices. Murphy participated in the 2007 Rock the Vote Ireland campaign targeting young voters for the general election. He has also campaigned for the rights of the homeless with the organization Focus Ireland.