Morrissey joined
Blackburn Rovers' youth setup in 2008, aged 16, after playing for local side Ringmahon Rangers. He returned to Ireland two years later, and signed for
Cork City. Morrissey made his debut on 29 May 2010, coming on as a late
substitute in a 0–1 home loss against
Athlone Town for the
First Division championship. He achieved promotion to the
Premier Division in 2011, appearing regularly, and was an ever-present figure for the club in the following campaigns. On 22 December 2014, Morrissey moved to
League Two's
Cambridge United. He made his U's debut on 3 February 2015, replacing
Luke Chadwick in the 51st minute of a
FA Cup 0–3 loss against
Manchester United at
Old Trafford. It was announced he had re-signed for home club
Cork City on 10 December 2015, ahead of the 2016 season. Morrissey announced his retirement from professional football on 2 December 2021 after 335 professional appearances, scoring 30 goals. ==International career==