[1] He oversaw new editions of the Bible and the Book of Common Prayer in Welsh.
Williams was born the son of Samuel Williams, Vicar of Llandyfriog and Rector of Llangynllo, Cardiganshire, and his wife, Margaret, daughter of Jenkin Powell Prytherch, in Y Glaslyn, near Llandysul, Ceredigion, in south-west Wales.
Williams later served as Curate of Chiddingstone, Kent (1708–1713), Vicar of Llanwenog, Cardiganshire (1715–1742), Vicar of Defynnog (Devynock), Brecknockshire, where his name is carved on one of the attic beams of the rectory (1716–1732), Rector of Chilton Trinity, Somerset, and finally Vicar of St Mary's, Bridgwater, Somerset (1732–1742).
Williams supervised new editions of the Bible and the Anglican Book of Common Prayer in Welsh.
Williams worked closely with Edward Lhuyd on the Archaeologia Britannica (1707) and with William Wotton on the Leges Wallicae, a parallel text edition of the laws of Hywel Dda, published in 1730.