Tegla’s father was a quarryman; following a serious injury he moved to work in the limeworks in Minera and the family moved to Pentre’r Bais (Gwynfryn) in 1896 and to Bwlchgwyn in 1896. So it was that at the age of 14 Tegla became a pupil-teacher at Bwlchgwyn school, where under the influence of the young schoolmaster, Tom Arfor Davies, he became interested in the history and literature of Wales. Attending preaching meetings in Coedpoeth he experienced a dramatic religious conversion and determined to enter the ministry. He was accepted into the probationary ministry in 1901 in Ffynongroyw, and went to college in Didsbury, Manchester. He was a minister in Abergele, Leeds, Porthaethwy, Y Felinheli, Tregarth, Llanrhaeadr-ym-Mochnant, Denbigh, Manchester, Liverpool, Bangor and Coedpoeth. He retired to Bangor in 1946, because of his wife’s ill health, and was widowed in 1948.
Although he never studied Welsh in school or University he became one of the most prolific authors of the language in his time. Tegla’s works include a number of children’s books which display his rich imagination and sometimes surreal humour, his only long novel Gŵr Pen y Bryn (1923, later translated into English as The Master of Penybryn (1975)), short stories and a series of essays. Many of his stories about fictional and biblical characters were first published in y Winllan, a Methodist periodical which he edited from 1920 to 1928.
Tegla regarded himself as a rebel to the end of his life. Although he was one of the most prominent and influential preachers of his denomination, and president of the Welsh Methodist Assembly in 1937, he was always a satirist of institutions, be they secular or religious. He was one of the early promoters of Biblical criticism in Wales. For many years he was a member of the council and executive committee of the National Eisteddfod and a frequent eisteddfod adjudicator. He received an honorary M.A. degree of the University of Wales in 1924 for his contribution to Welsh literature, and a D.Litt. in 1958.