His poems first appeared in the Summer 1958 and October 1959 issues of Delta. The publication of his poem Metamorphosis in the Times Literary Supplement in January 1960 brought his work to a wider audience. His first collection Once Bitten Twice Bitten was published by Scorpion Press in 1961. Influences on his work include: W. H. Auden, John Ashbery, and Wallace Stevens.. He went through distinct poetic stages, from the epigrams and satires of his early works Once Bitten Twice Bitten, to the elegiac mode of his later ones; The Cost of Seriousness and English Subtitles. In a recorded conversation with his friend Clive James he stated that the "glory of present-day English writing in America, in Australia and in Britain, is what is left over of the old regular metrical pattern and how that can be adapted to the new sense that the main element, the main fixture of poetry is no longer the foot (you know, the iambus or the trochee) but the cadence. It seems that what is very important is to get the best of the old authority, the best of the old discipline along with the best of the new freedom of expression."
In 1983 Porter was a judge in the Man Booker Prize.