After graduating in theology from East London Missionary Training Institute (now Cliff College) he became a pastor.
Pursuing his ambition he became a missionary of the Welsh Calvinistic Methodist Foreign Mission to Khasi people in India from 1887 until his death.
He was educated at Capel Neuadd, Calvinistic Chapel at Nanternis, till he was twelve years of age.
Before he completed one year of pastoral service he found an opportunity to join missionary work in Khasi Hills in northeast India under the Welsh Calvinistic Methodist Foreign Mission, which was headquartered in Liverpool.
[1][6] Although Williams was a missionary among Khasis, his most historically notable work was his visit to Mizoram (was then Lushai Hills).
[7][8] In early 1891 Williams met Mizo prisoners, the tribal chiefs, at Sylhet jail who were imprisoned after their defeat in the British expedition.
He met Benjamin Aitken, an elder of Free Church of Scotland and sub-editor of Calcutta-based newspaper The Englishman, who volunteered to join him in his expedition.
Here they stayed for four days and saw the first thatched huts of Mizos at a distant hill top, including stockades used during the British military expedition.
On Monday afternoon they arrived at Changsil, where they camped among the military escort commanded by Captain Williamson.
They stayed there for four weeks, learning about Mizo lifestyle, distributing Bible pictures and preaching among non-Mizo such as Khasi, Manipuri, and Naga workers stationed there.
He published his appeal to open mission field in Lushai Hills in June and July 1891 issue of Y Goleuad.
However, the date of his arrival, 15 March, was adopted as "Missionary Day" by Mizoram Presbyterian Church in its 89th General Assembly in 2012.