Hirst studied at Glasgow Academy and the University of Glasgow. Before entering politics, Hirst had a career as a chartered accountant and partner in Peat Marwick, now KPMG.
He was PPS at the Department of Energy from 1985 to 1987. He attempted to retake Strathkelvin and Bearsden in 1992 election but was beaten again by Galbraith, the same year he was knighted. In 1997 he was forced to resign his position as Scottish Conservative Chairman and Westminster candidate for the seat of Eastwood, in the wake of revelations about his private life, as he had had several previous homosexual affairs with other, younger Scottish Tories.[1][2][3]
After Parliament
Hirst was subsequently the president of the Scottish Conservative and Unionist Association from 1989 to 1992 and chairman of the Scottish Conservative Party from 1993 to 1997, having been vice-chair 1987–1989.
He was knighted in 1992 for political and public service in 1992. He is chairman of the Scottish Division of ISKB, and a member of its council.
He was the first non-medical chairman of the board of trustees of Diabetes UK from 2001–2006 and was elected vice president of the International Diabetes Federation in 2006, serving in that position until he was elected president-elect in 2009. He took up office as president at the end of 2012, serving until December 2015.