Gruffydd published his first volume of poetry,
Telynegion ("Lyrics") jointly with his friend and fellow-poet
R. Silyn Roberts in 1900, having written its contents in the summer of 1899 before he left for Oxford. Although Gruffydd would later regard his own contributions to the volume as juvenilia, the volume would later be compared to
Wordsworth and
Coleridge's
Lyrical Ballads in heralding a new era in Welsh poetry. Alongside poets such as R. Silyn Roberts,
T. Gwynn Jones,
R. Williams Parry he is associated with a "renaissance" in Welsh poetry at the turn of the century associated with a late resurgence of
romanticism. Although his total poetical output is comparatively small, due in part to the pressures of his academic work, it was of a very high standard and he was a major voice in Welsh-language poetry of the first two decades of the 20th century. He won the
Crown at the
National Eisteddfod in 1909 for his Pryddest on
Yr Arglwydd Rhys (
Rhys ap Gruffudd; no relation). After graduating in English at Oxford he became a schoolteacher and worked in
Scarborough and then for two years at
Beaumaris Grammar School before taking a post as assistant lecturer in Celtic studies at
University College, Cardiff, in 1906; from 1918 he was appointed Professor of Celtic and held the post in 1946. He was instrumental in the transformation of the study of
Welsh literature at universities in Wales. When he began teaching at university level, students of "Celtic" (as it was referred to then) would study no literature more recent then 1800 and almost nothing after 1500; the language of instruction was English even though all present would be fluent Welsh speakers and the subject matter in Welsh, and the students' main contribution was in translating passages into English. Although Gruffydd was one of many academics to react against this state of affairs, he was key in leading the transformation and the department at Cardiff was the first to teach the literature of the 19th century, the first to lecture in Welsh, the first to be referred to as a department of "Welsh" rather than "Celtic" (Ironically Gruffydd also introduced Irish and Breton literature to the syllabus, making the course more genuinely "Celtic" than it had ever been when referred to as such). Within a few years the other Welsh universities had all followed most of these innovations. He was President of Council of the
National Eisteddfod of Wales and edited
Y Llenor ('The Writer', a highly influential
Welsh-language journal of literature published by the university). As a researcher and academic he wrote a large number of books and articles and remains one of the key figures of his age in Welsh literary studies. ==Politics==