Martin was born and raised in Gosforth in Newcastle-Upon-Tyne. He has lived in East Lothian since 2004 and currently lives in Prestonpans with his wife Rachel and their two sons.
He worked as a teacher at Prestonpans Primary School from 2007 until his election to the House of Commons in June 2017. He represented East Lothian in the UK Parliament until the December 2019 General Election. Following the election he returned to teaching at Dirleton Primary School.
Before becoming a teacher, Martin had achieved a BA (Hons) Business Law degree from Huddersfield Polytechnic and worked as a Solicitor between 1989 and 2001. He retrained as a teacher at the University of Edinburgh, achieving a PGCPE pass with merit in teaching in 2002. He has been a Council Member of the General Teaching Council for Scotland (GTCS) and an active member of the EIS teaching union.
Outside of his professional life, Martin has been actively involved in the local community since moving to the county, including serving as Chair of Prestonpans Community Council.
On 6 May 2021 Martin was elected to the Scottish Parliament from the South Scotland Region, which includes the East Lothian constituency area. He is Scottish Labour’s shadow minister for children and young people, lifelong learning and youth unemployment. He is also the Convenor of the Parliament’s Standards, Procedures and Public Appointments Committee.