Sullivan signed for
Hamilton Academical on 2 January 2009 from Irish side
Bohemians. He made his professional debut on 26 December 2009, in a
Scottish Premier League match against
Celtic. Sullivan left Hamilton at the end of the 2009–10 season to return to Ireland, spending the 2010 season with
Limerick, before moving to
Shelbourne in time for the 2011 season. Sullivan left
Shelbourne on 30 July 2012. Sullivan signed for
Dundalk on 8 January 2013. On 12 December 2015, Sullivan signed for
Galway United for the 2016 season. On 4 March 2016, in the season opener against
St Patrick's Athletic at
Richmond Park, Sullivan made his debut and scored an 83rd-minute header in a 3–1 win. Despite the great start to his time at
Galway United, it was announced on 28 June 2016 that Sullivan had left the club citing travel issues. Sullivan re-signed for
Bray Wanderers in July 2016. He left Bray after their 2018 season, spending 2019 playing with amateur teams
Bluebell United and
Crumlin United. He then stopped playing at 28 years old and joined
DLR Waves as a coach for their
2020 season. On 9 September 2025, Sullivan was appointed as the interim head coach of
Athlone Town for the remainder of the
2025 season. Sullivan's first game in charge was a 3–0 defeat to
Glasgow City, on 10 September 2025 in the clubs inaugural appearance in the
UEFA Women's Europa Cup. ==References==