McGarvey hails from Armagh, Northern Ireland, and began his career as a stills Photographer before attending film school at the University of Westminster in London. Upon graduating in 1988, he began shooting short films and documentaries, including Skin, which was nominated for a Royal Television Society Cinematography Award, and Atlantic, directed by Sam Taylor-Wood. The latter project, an experimental, three-screen projected film created in 1997, earned Taylor-Wood a nomination for the 1998 Turner Prize, and would lead to an ongoing collaboration between McGarvey and the Director.