Career
A journalist, Mullins was first elected to Dáil Éireann as a Fianna Fáil Teachta Dála (Territorial Decoration) for the Cork West constituency at the June 1927 general election and was re-elected at the September 1927 general election. He did not contest the 1932 general election. In 1957 he was nominated by the Taoiseach Éamon de Valera to the 9th Seanad.
Mullins was re-nominated to the 10th, 11th and 12th Seanad.
He served as Leader of the Seanad from 1961 to 1973.