David Howell attracted the attention of John Griffiths (1820-1897) (q.v.), then rector of S. Mary Hill, who persuaded him to go to the ‘Eagle School,’ Cowbridge. He then went to a tutorial school at Merthyr from which he proceeded to the Llandaff church training college at Abergavenny. He was ordained deacon in 1855 by the bishop of Llandaff, and priest in 1856. From 1855 to 1859 he was a curate at Neath under his patron, by that time archdeacon Griffiths, and from 1857 to 1861 was secretary of the Church Pastoral Aid Society. He was appointed successively vicar of Pwllheli (1861), vicar of S. John's, Cardiff (1864), vicar of Wrexham (1875), and vicar of Gresford (1891). In 1877 he was given the degree of B.D. by the archbishop of Canterbury; in 1885 he became prebendary of Garth Felyd and honorary canon of S. Asaph; in 1889 he became archdeacon of Wrexham. In 1897 he was appointed dean of S. Davids.

In his younger days Llawdden, like his father, had turned out englynion and other poems. He became well known as a fluent eisteddfod orator, as a public lecturer, and as a preacher. He published a couple of pamphlets — Foreign missions, their progress during the reign of Queen Victoria … 1879, and Welsh Nationality: an address delivered … before the Welsh National Society of Liverpool … Dec. 1st 1901, 1902 — and articles in Y Cyfaill Eglwysig and other periodicals. His churchmanship was Evangelical — and Welsh-speaking. He d. at S. Davids, 15 Jan. 1903, and a memorial tablet was erected to him in the cathedral.