The candidate reaching a majority of votes cast wins the nomination, and is formally appointed as Taoiseach by the President in Áras an Uachtaráin.
Before 2016, all successful candidates obtained the votes of 50% or more of the house, but following the 2016 election, Enda Kenny was elected with the votes of just over one-third of TDs after Fianna Fáil abstained as part of a confidence and supply arrangement.
The Ceann Comhairle casts a vote only in the case of a tie.
From 6 December 1922 to 29 December 1937, during the period of the Irish Free State, the head of government was the President of the Executive Council, who was nominated by Dáil Éireann, and appointed by the Governor-General.
A breakdown of votes is on the pages of governments formed, while support for unsuccessful candidates is noted below.