Mullin was born in Bellshill. He was educated at Hutchesons' Grammar School, the University of Glasgow (where he was editor of the Glasgow University Guardian), and City University in London.[1][2] His first paid job in journalism was at the Western Morning News, then in 1987 he became a business reporter at The Independent. He moved to The Guardian, where he worked for ten years, latterly as Ireland correspondent, before his appointment in 2000 as Deputy Editor of The Scotsman. He returned to The Independent in 2003 as Executive Editor,[3] and was appointed as Editor of The Independent on Sunday in 2008.[4]
His departure as editor of The Independent on Sunday was announced in February 2013,[5] and he was replaced in April by Lisa Markwell.[6]