Simpson was educated at Perth Academy, Trinity College Glenalmond, and the University of Edinburgh.

As appointed Reporter to the Health and Community Care Committee, he produced three reports on the Stobhill Medium Secure Unit consultation process by Greater Glasgow Health Board, influenza vaccination in Scotland and organ donation.

Simpson was returned to the Scottish Parliament in 2007 as third on the Labour regional list for Mid Scotland and Fife.

In 2007, along with other opposition MSPs, he raised concerns about plans for local licensing boards to ban under 21 alcohol sales, stating that this would discriminate against young people who were responsible drinkers.

[6][7][8] Simpson was appointed Officer of the Order of the British Empire (OBE) in the 2017 Birthday Honours for services to Scottish politics and public life.