As a high-profile senator, the Malahide-based O'Brien has been active and visible locally and nationally since losing his seat in 2011. He was first elected to Fingal County Council in 2004 and became a TD for the constituency which was then known as Dublin North in 2007. He was unable to win re-election last time out after Fianna Fáil lost all but one of their Dublin seats. He then successfully ran for the Seanad under the Labour panel and was the leader of Fianna Fáil in the upper house until his he topped the pole in this election. He spent the five years after losing his seat assiduously building and reinforcing his power base across the north county Dublin constituency and his team has been fiercely protective of their patch. In the run-up to the election his team made headlines after being involved in a turf war of sorts with campaigners supporting running mate Lorraine Clifford Lee. He is married with one child. – CONOR POPE