He previously played with Barnet and Exeter City. Club
= Peterborough United O'Flynn began his career as a trainee with Peterborough United. = Cork City O'Flynn spent six years with Cork City, winning the League of Ireland and FAI Cup.
= Barnet In 2008, O'Flynn returned to England to play for Barnet. O'Flynn endeared himself to Barnet fans and was likened to club legend Giuliano Grazioli by former manager Paul Fairclough for his goalscoring ability. He was voted Barnet FC Player of the Season in 2008-9 by the clubs' supporters.
On 1 February 2010, transfer deadline day, he rejected a £100,000 move to Shrewsbury Town. On 1 July 2010, he joined Bristol City on trial, after turning down a new contract offer from Barnet. On 20 July 2010, O'Flynn left Ashton Gate after not being offered a permanent contract.
= Exeter City On 23 July 2010, O'Flynn signed a two-year contract with Exeter City. After two seasons in League One, he signed his second contract with Exeter in July 2012. O'Flynn was released by the club on 15 June 2015 after scoring 25 goals in 133 appearances over four seasons at St James Park.
= Return to Cork City On July 1 2015 O'Flynn signed back for his former club until the end of the season. Limerick FC
At the end of the 2015 season, O'Flynn joined Cork City's Munster rivals Limerick FC in the SSE Airtricity First Division.