Marc was first selected as a candidate in 2014 to contest the seat of Carmarthen West and South Pembrokeshire in the Assembly elections held in 2016.

Since then, he has campaigned on a variety of social justice, environmental and local issues such as supporting the delivery of high quality, accessible health services to the successful scrapping of the Cleddau Bridge tolls.

Marc stood for election to the UK Parliament in 2017 and 2019, again for Carmarthen West and South Pembrokeshire where he put forward ideas on developing a Green New Deal to support the green jobs of the future boosting our rural, coastal economy whilst taking sensible measures to lessen our impact on the environment.   Marc also campaigned for the inclusion of Redstone Cross outside Narberth as part of the wider A40 Llanddewi Velfrey bypass scheme using the last of the available finance from the EU to complete the works.

Marc successfully fought the closure of Narberth Library and with the help of the Town Council and strong group of volunteers, library services in the town have been protected and enhanced.

In May 2022, Marc campaigned for a stronger, fairer and greener Narberth and won the Narberth Urban council seat for Labour with 74% of the vote.