Born in London, Howson moved to Glasgow at the age of four. He studied at Glasgow School of Art from 1975 to 1977, was briefly in the army, then returned to the art school from 1979 to 1981. He was a contemporary of Steven Campbell, Adrian Wiszniewski and Ken Currie. Howson's paintings are mainly of the Glasgow underclass. At times Howson portrays this overtly working-class, masculine world with sympathy and tenderness; at other times he portrays it as a seething hotbed of violence. Howson was appointed British Official War Artist for Bosnia in 1993. He has increasingly turned to Christian subjects in recent works.