Answer
The answer is Vice-President of the Executive Council. Prior to the enactment of a new Irish constitution in 1937, Éamon de Valera held the role of President of the Executive Council of the Irish Free State, while Seán T. O'Kelly concurrently served as his deputy. The title reflected the Irish Free State's semi-autonomous status within the British Empire at the time, emphasizing self-governance while still formally recognizing the British monarchy.