Career
He was a Teachta Dála (TD) for the Cork South–West constituency from 2007 to 2011. He was re-elected to the County Council at the 2004 local elections, and in January 2007 he joined Fianna Fáil, and was imposed as a Fianna Fáil candidate for the 2007 general election, without a selection conference. The strategy partly worked.
Under the Local Government Act 2001, O'Sullivan vacated his council seat when elected to the Dáil. He was arrested on suspicion of drink driving on 2 June 2008, he has apologised after failing a breath test near Clonakilty. On 4 November 2008, he was banned for driving for 1 year and fined €300 after pleading guilty to a charge of drink driving.
He lost his seat at the 2011 general election.