Born and brought up in Rathdrum, County Wicklow, Máire went to London to receive an education as a secretary and became interested in the cause of Irish independence. On her return, she joined Sinn Féin in Gorey and was a witness to the events of the Easter Rising in Dublin. She gained employment with Alice Stopford-Green and met many of the major figures involved in the War of Independence during her time in residence with Mrs Stopford-Green on St Stephen’s Green. During the Civil War, Máire joined the White Cross and was in the Four Courts during the last days before its destruction. She was also involved in travelling to America to raise money for Sinn Féin.

In 1935, Máire joined the Irish Press as a journalist and stayed with the newspaper until her retirement in 1965. Throughout her life Máire was heavily involved in the republican cause and was arrested at the age of eighty-one on a Sinn Féin platform in Dublin. She has one published work entitled The First Dáil, January 21st 1919 (Dublin: J. Clarke, [1969]) in which she examined the formation and working of the first Dáil Éireann.