The Secretary's signature is essential for the authentication of the Presidential Seal when affixed to a document executed by the Commission under Seal.
Under the Presidential Elections (Amendment) Act, 1946 the Secretary to the President is one of a group of senior state officials, including the outgoing president, the Taoiseach and the chairs of both houses of the Oireachtas, who must be formally notified of the election of a new president by the Returning Officer.
The coming into force of the new Irish constitution, Bunreacht na hÉireann, in December 1937 resulted in the creation of a new office, President of Ireland. While the office was not scheduled to be filled until mid 1938 its powers, functions and duties were required to be exercised immediately. That role was given to the new collective vice-presidency, which under the transitory provisions of the constitution was made up of the Ceann Comhairle (speaker) of Dáil Éireann, the Chief Justice and the President of the High Court. (The latter fulfilled the role that would normally be exercised by the Cathaoirleach (chairman) of Seanad Éireann. However the election to the new upper house had yet to take place, so there was no Cathaoirleach.)
The Government immediately appointed as Secretary to the President Michael McDunphy, a controversial, outspoken and temperamental civil servant who had prior to his appointment been Assistant Secretary to the Executive Council, and had once been Secretary to the Provisional Governments of Michael Collins and W. T. Cosgrave (January-December 1922) McDunphy, like the Presidential Commission, was originally based in Dublin Castle until a new presidential residence was chosen. He moved into the new Áras an Uachtaráin (formerly the Viceregal Lodge) in June 1938.
McDunphy had a longterm impact on the presidency. His 1945 book The President of Ireland: His Powers, Functions & Duties was seen as the bible of the office by those seeking to restrict the post and its occupant. His restrictions, which were viewed as correct (or, if not correct, useful in enabling them to control and restrict presidents) by later civil servants, led President Erskine Childers to accuse on later Secretary to the President of having "the ghost of McDunphy behind you." Mary Robinson as president ditched all of McDunphy's rules and in effect started from scratch. Commentators credited the ditching of McDunphy's rules as a key factor in the rebirth of the office and in its subsequent popularity.