Thomas Macdonald was born on 22 November 1900 at Llanfihangel Genau'r Glyn in Cardiganshire, the son of John Macdonald (1860–1938), a tinker of Irish descent, and his second wife Ada Jones (1878–1946). He spent his early childhood in a small cottage in the village, before moving with his family first to Pen-y-garn and then going on to live in nearby Bow Street. According to his father the family name was actually MacDonnell, but had been inadvertently changed to Macdonald by the local registrar of births and deaths.
