He is a self-taught multi-instrumental musician who began his career in the 1980s, working with fellow Liverpool-natives The Lotus Eaters and Thomas Lang, as well as Claudia Brücken.

His early film score career saw him work David Hughes from the electronic group OMD, and he has collaborated with directors Danny Boyle, Guy Ritchie, Michael Mann, Matthew Vaughn, Stephen Frears, and James Gunn.

Born on 4 March 1965 in Liverpool, England, Murphy's interest in music was sparked when he heard The Beatles rendition of "Twist and Shout", which was the first song he learnt on the guitar.

Other excerpts from his scores have been used for advertising, film trailers, television shows and video games, in particular "In the House – In a Heartbeat" from 28 Days Later, and "Adagio in D Minor" from Sunshine; the former has featured in a number of tense situations on TV shows, such as the BBC's Top Gear, Dragon's Den, The Apprentice and MasterChef.

The score was allowed to develop in directions unconstrained by the original film's narrative[6] and the cover art is a photograph of Murphy's son, taken by his wife through her sunglasses.