At Bangor he had studied music and mathematics, but after leaving college he was influenced by Thomas Carlyle and William Ellery Channing and developed an interest in Theology.
He remained for a further year at Cambridge and in 1887 was appointed lecturer at Owen's College in Manchester as assistant to Robert Adamson.
[1][2][3] Prys began to preach in 1883 and quickly came to notice for the enthusiasm, depth and intelligence of his sermons.
In 1904 he delivered the ‘Davies Lecture’ at Cardiff on ‘The Doctrine of Man.’ He was elected Moderator of the General Assembly in 1910 and of the South Wales Association in 1917.
He was again elected Moderator of the General Assembly of the Presbyterian Church of Wales for the 1935 bi-centenary celebrations of the denomination but died in December 1934 before he could take up that office.