Cian O'Sullivan (born 27 March 1988) is a Gaelic footballer who plays for the Kilmacud Crokes club and previously at senior level for the Dublin county team.
He was a key performer in the game ultimately moving to corner back following an injury to Jonny Cooper in Dublin's defeat of Mayo on a scoreline of 2–12 to 1–14.
Following defeat to Donegal in 2014, manager Jim Gavin deployed him as a "sweeping centre back", responsible for shoring up Dublin's defense against leaking goals.
He also played a key role as the Dubs defeated Mayo by a single point after a replay on a scoreline of 1–15 to 1–14 to retain the Sam Maguire Cup.
On 17 September, O'Sullivan was heavily involved as Dublin claimed a historic 3 in a row All Ireland titles with another narrow 1–17 to 1–16 victory against Mayo.