Background
He was born in Cloughjordan, Tipperary, the brother of the executed 1916 Easter Rising leader Thomas MacDonagh and film director John MacDonagh.
He was born in Cloughjordan, Tipperary, the brother of the executed 1916 Easter Rising leader Thomas MacDonagh and film director John MacDonagh.
He was elected unopposed as a Sinn Féin Member of Parliament for the Tipperary North constituency at the 1918 general election. In January 1919, Sinn Féin MPs refused to recognise the Parliament of the United Kingdom and instead assembled at the Mansion House in Dublin as a revolutionary parliament called Dáil Éireann, though MacDonagh did not attend as he was in prison. He was elected unopposed as a Sinn Féin Teachta Dála (Territorial Decoration) for the Tipperary Mid, North and South constituency at the 1921 elections.
He also served as an alderman of Rathmines Urban District Council and Dublin Corporation between 1920 and 1922.
He was Director of the "Belfast Boycott", an attempt in 1920-1921 to boycott goods from Ulster that were being imported into the south of Ireland. He opposed the Anglo-Irish Treaty and voted against lieutenant
He was re-elected for the same constituency at the 1922 general election, this time as an anti-Treaty Sinn Féin Territorial Decoration, but he did not take his seat in the Dáil. He died on hunger strike on Christmas Day 1922.
31st United Kingdom Parliament.