[3] A fan of horse-racing,[4] in 1987, he also established Seán Barrett Bloodstock Insurances Ltd.[3] He first became involved in local politics, serving on Dublin County Council from 1974 until 1982.

"[4] When Barrett, Liam T. Cosgrave and Monica Barnes were each first elected in 1981, Fine Gael secured three of the five seats and 48% of the first preference vote in Dún Laoghaire.

But this massive vote waned over the following years and when Barrett and Barnes retired at the 2002 general election, Fine Gael failed to win even one seat in Dún Laoghaire.

[15] At a selection meeting in Dalkey in May 2006, Barrett and barrister Eugene Regan were chosen as Fine Gael's two candidates in the Dún Laoghaire constituency.

[7] Barrett did not return immediately to Fine Gael's front bench, but became Chairperson of the Oireachtas Joint Committee on Climate Change and Energy Security.