She was educated in University College Dublin where completed her teacher's diploma and got involved in the Irish Nationalist organisation Cumann na mBan partly through the advice of her mentor, Professor Boden.
[2][5][6][better source needed][7][8] In September 1920, Nic Eachnaidh began working as an Irish, History and Geography teacher in Scoil Bhride in St. Stephen's Green.
Like all the women involved in the war, Nic Eachnaidh carried messages, hid and transported weapons and provided first aid services.
[2][5][9][10][11] Once the truce came into effect Nic Eachnaidh was one of the women against the acceptance of the articles of the Anglo-Irish Treaty she remained a believer in the idea of an independent Republic and she continued her activities in opposition to the Free State.
[2][5] In the aftermath of the Irish Civil War, Nic Eachnaidh remained involved working for pensions for those who had been in the various forces as well as looking for support for those prisoners who had been members of the IRA.