In 1922, Sir John was nominated by the President of the Executive Council to Seanad Éireann of the Irish Free State, and served until 1934. In 1923 his home at Cappoquin House was burned by anti-government forces in the Irish Civil War, which he then rebuilt. He later served in the reconstituted Seanad Éireann established by the Constitution of Ireland, serving from 1938 to 1948 on the nomination of the Taoiseach. It has been said that, by this time, he was "widely regarded as the quintessence of intelligent ex-unionism".