Damian was first elected as the Conservative Member of Parliament for East Hampshire in May 2010. He was re-elected to this position in May 2015, and again in June 2017.

Damian held the position of Secretary of State for Education between January 2018 and July 2019, and was previously Minister for Employment at the Department for Work and Pensions from July 2016 to January 2018. Prior to that, Damian held the position of Exchequer Secretary to the Treasury; an appointment he took up in May 2015, and was an Assistant Government Whip between July 2014 and May 2015.

He had previously served on the Education Select Committee and chaired the Social Mobility All-Party Parliamentary Group.