Raised in Belfast, she was educated at Trinity College, Dublin, where she took BA and PhD degrees, and won the Patrick Kavanagh Poetry Award in 1990. She has published four collections of poetry: There Was Fire in Vancouver (1996), Between Here and There (2001), The State of the Prisons (2005), and Through the Square Window (2009), the second, third and fourth of which were shortlisted for the T. S. Eliot Prize. After periods living in Japan and New Zealand she now lives in Belfast, where she has been writer-in-residence at Queen’s University, Belfast and currently lectures.

Her collection, The State of the Prisons, was shortlisted for the Poetry Now Award in 2006. The same collection won the Michael Hartnett Poetry Prize in 2005. In November 2007, she received a Lannan Foundation Fellowship for “distinctive literary merit and for demonstrating potential for continued outstanding work”. Her poem “Through the Square Window” won first prize in the 2007 British National Poetry Competition. Her collection, Through the Square Window, won the Poetry Now Award for 2010.

In January 2014 Morrissey won the T.S. Eliot Prize for her fifth collection Parallax. The chair of the judging panel, Ian Duhig, remarked that the collection was ‘politically, historically and personally ambitious, expressed in beautifully turned language, her book is as many-angled and any-angled as its title suggests.’