[1] O'Sullivan won his first All-Ireland Senior Football Championship in 2006, after a comprehensive victory over Mayo side in the final on 17 September 2006, in Croke Park.

Seán had an exceptional season, being responsible for many of the passes which made Kieran Donaghy a real threat to defences in 2006.

[citation needed] Since retirement O'Sullivan has become involved in coaching, selector and as a manager.

O'Sullivan was announced as manager of South Kerry GAA in March 2021.

This came alongside a role as a Kerry under-20 football team selector under the management of Declan O'Sullivan.