
The current Constitution of Ireland came into effect on 29 December 1937, repealing and replacing the Constitution of the Irish Free State, having been approved in a national plebiscite on 1 July 1937 with the support of 56.5% of voters in the then Irish Free State. The Constitution was closely associated with Éamon de Valera, the President of the Executive Council of the Irish Free State at the time of its approval.

The Constitution of the Irish Free State was adopted by Act of Dáil Éireann sitting as a constituent assembly on 25 October 1922. In accordance with Article 83 of the Constitution, the Irish Free State Constitution Act 1922 of the British Parliament, which came into effect upon receiving the royal assent on 5 December 1922, provided that the Constitution would come into effect upon the issue of a Royal Proclamation, which was done on 6 December 1922. In 1937 the Constitution of the Irish Free State was replaced by the modern Constitution of Ireland following a referendum.

Dáil Éireann served as the directly elected lower house of the Oireachtas of the Irish Free State from 1922 to 1937. The Free State constitution described the role of the house as that of a "Chamber of Deputies". Until 1936 the Free State Oireachtas also included an upper house known as the Seanad. Like its modern successor, the Free State Dáil was, in any case, the dominant component of the legislature; it effectively had authority to enact almost any law it chose, and to appoint and dismiss the President of the Executive Council. The Free State Dáil ceased to be with the creation of the modern 'Dáil Éireann' under the terms of the 1937 Constitution of Ireland. Both the Dáil and Seanad sat in Leinster House.

The Great Seal of the Irish Free State is either of two seals affixed to certain classes of official documents of the Irish Free State :the "internal" Great Seal, used from 1925 for "internal" documents signed by the Governor-General the "external" Great Seal, used from 1932 for diplomatic documents signed by the British king.

The Local Government Act, 1925 was enacted by the Oireachtas of the Irish Free State on 26 March 1925. Most of the provisions of the Act came into operation on 1 October 1925.

From its foundation on 6 December 1922 until 11 December 1936, the Irish Free State was in accordance with its constitution, governed formally under a form of constitutional monarchy. The monarch exercised a number of important duties, including appointing the cabinet, dissolving the legislature and promulgating laws. Nonetheless, by convention the monarch's role was largely ceremonial and exercised on his behalf by his official representative, the governor-general. The monarch's role and duties under the constitution were ended under a constitutional amendment adopted in 1936. From that point, the monarch no longer played any role in appointing the cabinet, dissolving the legislature or promulgating laws. Nor was the monarch mentioned anywhere in the constitution. Under separate legislation also adopted in 1936 it was provided that Irish diplomatic representatives would be appointed on the authority of the cabinet alone and international agreements would be concluded with the authority of the cabinet alone. At the same time, that legislation also created a new role for the king in his capacity as the "symbol of [the] co-operation" of Australia, Canada, Great Britain, New Zealand, and South Africa for so long as the Irish Free State was associated with those states. The new role of the king in that capacity alone was to act on behalf of the Irish government with respect to the appointment of diplomatic and consular representatives and the conclusion of international agreements when advised by the cabinet so to do. The role of the king in acting on behalf of the Irish government with respect to appointing diplomats was not ended until 1949 and under United Kingdom law the king is regarded as having been the sovereign until that time but not under Irish law.

The Oireachtas of the Irish Free State was the legislature of the Irish Free State from 1922 until 1937. It was established by the 1922 Constitution of Ireland which was based from the Anglo-Irish Treaty. It was the first independent Irish Parliament officially recognised outside Ireland since the historic Parliament of Ireland which was abolished with the Act of Union in 1800.

The president of the Executive Council of the Irish Free State was the head of government or prime minister of the Irish Free State which existed from 1922 to 1937. He was the chairman of the Executive Council of the Irish Free State, the Free State's cabinet. The president was appointed by the governor-general, upon the nomination of Dáil Éireann and had to enjoy the confidence of the Dáil to remain in office. The office was succeeded by that of Taoiseach, though subsequent Taoisigh are numbered from the first president of the Executive.

Seanad Éireann was the upper house of the Oireachtas (parliament) of the Irish Free State from 1922 to 1936. It has also been known simply as the Senate, First Seanad, Free State Senate or Free State Seanad. The Senate was established under the 1922 Constitution of the Irish Free State but a number of constitutional amendments were subsequently made to change the manner of its election and its powers. It was eventually abolished in 1936 when it attempted to obstruct constitutional reforms favoured by the government. It sat, like its modern successor, in Leinster House.

The Supreme Court of the Irish Free State was the state's court of final appeal. It was created in Article 64 of the Irish Free State Constitution. It was presided over by a Chief Justice. The number of judges on the court was laid down in the Courts of Justice Act 1924.

The Vice-President of the Executive Council was the deputy prime minister of the 1922–37 Irish Free State, and the second most senior member of the Executive Council (cabinet). Formally the Vice-President was appointed by the Governor-General on the nomination of the President of the Executive Council, but by convention the Governor-General could not refuse to appoint a Vice-President who the President had selected.