Selwyn was born in Caernarfon in 1933. After completing National Service he studied at Bangor College from 1954 to 1956 and went on to teach Art at Ysgol Syr Hugh Owen and Maesincla Primary School until his retirement in 1990. He then immersed himself into painting full-time. Selwyn is recognised as a landscape watercolourist, whose works reveal a fascination with the coastline of Gwynedd and its farm workers and fishermen. The winner of a number of coveted art prizes and a member of the Royal Cambrian Academy, he pushes the challenging medium of watercolour into new territory.