His three Welsh-language verse collections – Cerddi 1934–1942 (1944), Pont y Caniedydd (1956), and Y Golau yn y Gwyll (1979) – secured him a distinctive place in the poetry of his country as a thoughtful observer of 20th-century Welsh life in the context of the wider European experience.
The novelist and scholar Gwyn Jones wrote that he "says much to men of my generation that we dearly wish we could say ourselves about the course and aftermath of wars and depressions, the changing vistas of Wales and Welsh society, the hard-held hopes and ideals that no one else can carry for us, our regrets for good things lost and ploughed-in illusions.
After graduating he became known as a poet[1] and as the co-founder and editor, from 1935 to 1939, of Tir Newydd (New Ground), a magazine which examined literature, the other arts and global current affairs from an urban, socialist viewpoint.
[12][9] During these years he wrote much literary criticism, notably his 1960 volume Y Nos, Y Niwl a'r Ynys: Agweddau ar y Profiad Rhamantaidd yng Nghymru 1890-1914 [The Night, the Mist and the Island: Aspects of the Romantic Experience in Wales 1890-1914] (1960).
It cemented his reputation,[13] won the Main Poetry Prize of the Arts Council of Wales, and was translated into English by Joseph P. Clancy [cy] in 1988 under the title The Light in the Gloom.
He felt ambivalent about the use of cynghanedd (an intricate system of alliteration used for centuries past) in modern poetry, and about the element of competition in the eisteddfod.