Shay Brennan is a Fianna Fáil councillor for the Dundrum ward of Dublin Rathdown.

He was first elected Councillor in 2014. He serves on the Dundrum Area Committee, DLR Properties Board, the Mill Theatre Board, the Joint Policing Committee and the Organisation, Procedure and Protocol committee, as well as holding the role of championing and promoting cycling across the county. Shay is a former Cathaoirleach and Leas Cathaoirleach of Dún Laoghaire Rathdown County Council.

Shay is the son of the late Seamus Brennan. He was educated at Scoil San Treasa in Mt Merrion, Blackrock College and UCD, where he completed a BA in Economics and a MBS in Financial Services. His career spans a range of roles in the financial services industry both in Ireland, and internationally. Shay grew up in Dundrum and has been very active in local politics, policy and community work.