Matthew was born and grew up in Pembrokeshire, he has been a member and has competed for his local running club Pembrokeshire Harriers since the age of 11. His specialist events are the 800m and 1500m and he gained his first Welsh international vest in 2011 at the London mini marathon, since then he has gone on to gain many more on the road, cross country as well as on the track. The Pembrokeshire runners best achievements include gaining a welsh senior vest in the 800m during the Manchester international, as well as breaking the Welsh schools 1500m record and winning numerous Welsh athletics track and cross country races. Williams joined Cardiff Metropolitan University in 2017 and changed coaches to train with James Thie and the group, since this move; his cross country results have dramatically improved as well as improving his 1500 time by 6 seconds to 3:48. Matthew is optimistic for the future and has hopes set on getting back to form whilst staying injury-free.