Desmond was born in 1956 and was educated at Bedford School and St Andrews University. He was a school master from 1981 to 1987 and a manager with the Royal Bank of Scotland from 1987 to 1997 when he was elected to Parliament for the New Forest West constituency.
He has been a serving Territorial Army officer since 1987 and served in Iraq from July to December 2003. During this service he contributed a popular audio diary to BBC Radio Four. To keep fit, Desmond swims a quarter of a mile in the Serpentine daily throughout the year when Parliament is in session. He also runs through the New Forest between his home and Brockenhurst station to catch the train to London. He married Moira in 1987 and has three children. The family lives in the New Forest.
During the 2001-2005 Parliament, he served as Parliamentary Private Secretary to the Leader of the Opposition. In December 2005, he was appointed by the new Leader, David Cameron, to be his Parliamentary Private Secretary. In September 2012 he was appointed Lord Commissioner of HM Treasury.
Previously, he has held shadow ministerial portfolios for Northern Ireland, Health and Defence and has been a senior opposition whip. In the 1997-2001 Parliament, he was on the Social Security select committee.
Prior to his election in 1997, Desmond contested the Parliamentary seats of Pontypridd in 1987 and West Bromwich West in 1992. He also contested a district council and a county council seat in the West Midlands, and a London borough seat in North Kensington.