He has had several small parts in television and stage productions. Leaf is married to Actress Tamsin Greig since 1997 and has 3 children. The actor is notable for his role as the Governor of York, nephew of King Edward I in Mel Gibson's Braveheart. He appeared as Hannibal Lecter's father in the 2007 Hannibal Rising film. He also appeared as John Dawlish, an Auror, in the film Harry Potter and the Order of the Phoenix, and portrayed Jack, the bartender of the Cloverdilly public house, in the 2006 film, Penelope.