Gwyn was born into a farming family in North Wales and trained as an engineer with Rolls Royce and an engineering company in London, before returning to agriculture in Wales, studying at Coleg Meirion, and Glynllifon College of Agriculture.
Having completed his studies, Gwyn moved with his wife Lorayne and daughters Elin and Gwenan, to Moulton College of Agriculture, Northamptonshire, to run the beef and sheep units, before arriving at Crouchlands Farm in West Sussex as farm manager 31 years ago.
He is currently a dairy farmer, farming in partnership in West Sussex milking 750 cows on heavy weald clay, and has diversified into green energy with a one megawatt bio digester. A Nuffield Scholar and Fellow of the RASE, Gwyn was also the NFU National Dairy Board chairman for six years until becoming Vice President. His other roles with the organisation include being a member of the NFU Council, the chairman of Policy Board, and a member of Governance Board, as well as a director. In addition, he is a council member for the Farm Animal Welfare Council (FAWC), and a member of COPA Animal Health.
Gwyn was past vice chairman of COPA Milk, and served on the Milk Development Council (MDC) for seven years. He was also past chairman and member of the farm management and MDC evaluations committees.
Gwyn writes a weekly farming column for the West Sussex Gazette and regularly contributes articles for other journals and publications.