Gwyn was born in Cardiff and trained at Manchester, studying music there at the University and the RNCM. As a professional performer, he has worked with many of the country's top orchestras, and has played under the baton of some of the world's greatest conductors, including Barbirolli, Giulini and Rattle.
Gwyn has been conductor of, among others, UC Salford Choral Society, the Berkshire Camerata and Reading University Choral Society. He has held academic posts at the Universities of Oxford, Keele, Gothenburg, and Reading.
He is also well known as an adjudicator, and has been Chairman of the adjudicating panel in the National Festival of Youth Orchestras at the Royal Festival Hall. In 1998 Gwyn was elected Fellow of the Royal Society of Arts.