He began his career working for Sounds magazine in the 1970s, shooting various artists on the punk scene including The Clash, The Jam, The Sex Pistols, 999, and The Adverts. After linking up with writers Geoff Barton and Peter Makowski, Halfin moved on to working mainly in the United States with bands like Air Corps/District of Columbia, unidentified flying object, Rush, Journey, Aerosmith, and Black Sabbath. Halfin established Kerrang! magazine in 1980 with Barton and produced images of bands from that era.
He has toured with many bands, including Metallica, Iron Maiden, Def Leppard, Mötley Crüe, Van Halen, Aerosmith, The Black Crowes, Ozzy Osbourne, Kiss, Soundgarden, Queens of the Stone Age, and The Mars Volta.