[1] He graduated First Class Honours from the University of Liverpool in 1939, and then went to study town planning under William Holford.
[1] He spent the next seven years working with various architects in Cardiff, including contributions to the Alwyn Lloyd and Herbert Jackson South Wales Outline Plan.
[1] After retirement as a teacher, Thomas returned to practical architecture once more, contributing to the design of Y Pencadlys (County Hall) in Caernarfon,[1] the headquarters of Gwynedd County Council, executed by the Council's architects Merfyn Roberts and Terry Potter 1982–86.
[1] He also served as a commissioner on the Royal Commission on the Ancient and Historical Monuments of Wales, and a member of the Gorsedd of Bards.
[1] The triennial Dewi-Prys Thomas Prize is awarded by the Royal Institute of British Architects, and "recognizes the importance of good design to the quality of life, identity and regeneration of Wales".