His early works are typified by very masculine working class men. He was commissioned by the Imperial War Museum of London, to be the official war artist for the Bosnian/Hercegovina under Serbian and Croatian aggression in 1993, producing some of his most shocking and controversial work detailing the atrocities which were taking place at the time. One painting in particular, ‘Croatian and Muslim’, detailing a rape, created controversy partly because of its explicit subject matter but also because Howson had painted it from the victims’ accounts.
He was the official war painter at the Kosovo War for the London Times.
Howson was commissioned to design a British postage stamp which was produced in 1999, celebrating engineering achievements for the millennium. In addition his work has been used on album covers by Live (Throwing Copper), The Beautiful South (Quench) and Jackie Leven (Fairytales for Hardmen). His work is exhibited in many major public and private collections.
In 2009 he was appointed Officer of the Order of the British Empire (OBE).
In November 2010, BBC Scotland aired a documentary named “The Madness of Peter Howson” which followed the final stages of the completion of a grand commission for show in the renovated St Andrew’s Cathedral and also dealt with Howson’s struggle with mental illness and Asperger’s Syndrome
In September 2014, Howson suggested he would hand back his OBE, predominantly because of his dislike of British foreign policy.