Actor, Born in East Kilbride (South Lanarkshire), Bonnar moved with his parents to Stonehouse and then Edinburgh, where he was educated at Leith Academy. He began his career working for Edinburgh City Council working initially in a library and then in the planning department, where he was encouraged by colleagues to enter the world of amateur dramatics.
Following minor roles in Rebus (2001) and Taggart (2003), Bonnar has gone on to success in a number of television shows, including Casualty (2005-06), The Bill (2007), Doctor Who (2011), Psychoville (2011), Shetland (2013 - ), Line of Duty (2014), Catastrophe (2015-19), and Unforgotten (2017), which gained him a Scottish BAFTA award, and Guilt (2019). He has also had roles in a television adaption of Robert Louis Stevenson's Jekyll & Hyde (2015) and a film of Lewis Grassic Gibbon's Sunset Song (2015).
Bonnar now lives in Hertfordshire (England).
