Marion Fellows studied Accountancy and Finance at Heriot-Watt University and spent her early career in a variety of related roles in both the public and private sectors. She subsequently taught in further education, spending almost 20 years teaching business studies at West Lothian College, where she was an active and senior member of the EIS Trade Union.
She has lived with her family in Wishaw and Bellshill for over 40 years, and represented Wishaw as a local SNP Councillor from 2012 to 2015. She was a prominent figure in the Yes Motherwell and Wishaw campaign, which won a majority locally in the 2014 Independence Referendum.
Marion was elected as the Member of Parliament for Motherwell and Wishaw at the General Election in 2015. She was re-elected for a second and third term in 2017 and 2019.