Seamus graduated from Queen's University Belfast in May 1961. He then took a temporary Summer job working in the UK passport office in London.
Following this, he returned as a student to St. Joseph's Teacher Training College in Belfast for one year and began teaching in St. Michael's Secondary School in Belfast. After one year he returned to St. Joseph's Teacher Training College as a lecturer and then became a lecturer at Queen's University where he remained until 1969. Faber & Faber Ltd published his first full collection of poetry, Death of a Naturalist, in 1966 followed by, Door Into the Dark, in 1969.
In 1969 he moved to California, USA and took up a position as lecturer in Berkeley University. In 1972 he returned to Ireland as a full time poet. Faber published his third collection, Wintering Out, in that year and fourth collection, North in 1975.
In 1976 he moved to Dublin and look up a position as lecturer in Carysfort College, another Teacher Training College. In 1979 Faber published his fifth collection, Field Work followed by a collection of prose, Preoccupations, in 1980.
He did a translation of the an ancient Gaelic text, Buile Suibhne, as Sweeney Astray, published by Field Day, Derry in 1983.
He was a professor at Harvard University in USA from 1981 to 1997 and its Poet in Residence from 1988 to 2006. From 1989 to 1994 he was also the Professor of Poetry at Oxford in England.
He has written two plays: The Cure at Troy A version of Sophocles' Philoctetes, Field Day, Derry, 1990; The Burial at Thebes A version of Sophocles' Antigone, Faber & Faber, 2004.
He wrote seven more collections of poetry; Station Island, 1984; The Haw Lantern, 1987; Seeing Things, 1991; The Spirit Level, 1996; Electric Light, 2001; District and Circle, 2006; Human Chain, 2010. Two more major translations: Beowulf, 1999; The Testament of Cresseid, 2004. And two more volumes of essays: The Government of the Tongue, 1988; The Redress of Poetry, 1995.