 Fitzsimons was elected to the 21st Dáil as a Fianna Fáil Teachta Dála (TD) for the Meath constituency on his first attempt at the 1977 general election, and re-elected until retiring at the 1987 general election to concentrate on his European Parliament seat.He was succeeded in the Dáil by Noel Dempsey.He briefly served as a Minister of State for Industry and Energy during the short-lived 1982 Haughey Government.