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 19 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 40 years, and represented Wishaw as a local SNP councillor from 2012 to 2015. She was a senior 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, 2017 and was re-elected for a third time in 2019.