Born in Rush, Dublin, Clarke worked for the Sinn Féin Bank, and was active in the Easter Rising.

On Easter Monday morning, on 24 April 1916, Clarke was one of 13 volunteers who held the Mount Street Bridge for nine hours against the overwhelming forces of the Sherwood Foresters Regiment of the British Army.

[6] Released in 1923, he acted as caretaker of the Sinn Féin headquarters on Harcourt Street,[4] and founded the Irish Book Bureau.

[3] Although the Anti-Treaty Sinn Féin rejected participation in the Dáil, they continued to contest local elections, and Clarke sat on Dublin City Council.

Clarke was ejected from an official commemoration of the fiftieth anniversary of the First Dáil for interrupting de Valera's speech in order to raise the complaints of the Dublin Housing Action Committee.