Kevin Christopher O'Higgins was born on 7 June 1892 in County Laois. He was educated at Clongowes Wood, St. Patrick's College Maynooth and University College Dublin. He joined Sinn Féin and was imprisoned in 1918. While he was imprisoned he became MP for Laois. In 1919 O'Higgins was appointed Assistant Minister for Local Government. He was strongly in favour of accepting the Treaty in 1921. In 1922 he was elected TD for Dublin. In the first government he became Minister for Justice and External Affairs, as well as Vice-President of the Executive Council (Deputy Prime Minister).
When the Irish Civil War broke out he tried to restore law and order by introducing tough measures. Between 1922 and 1923 seventy-seven Republican prisoners were executed by order of O'Higgins. O'Higgins also set up An Garda Síochána (an un-armed police force). As Minister for External Affairs he advocated a free and independent Ireland within the Commonwealth.