The Kingdom of Ireland was the name given to the English-ruled Irish state in 1541, by an act of the Irish Parliament. It replaced the Lordship of Ireland, which had been created in 1171. King Henry VIII thus became the first King of Ireland since the High Kingship which had existed before the Anglo-Norman invasion.

The Throne of Ireland was occupied by the reigning King of England. The Kingdom of Ireland was governed by an executive under the control of the Lord Deputy, later called Lord Lieutenant. While some Irish men held the post, most Lords Deputy were English noblemen.

It was legislated for by a bicameral Irish Parliament, made up of a House of Commons and a House of Lords, which almost always met in Dublin. The powers of the Irish parliament were restricted by a series of laws, notably Poynings Law of 1492. Roman Catholics were for much of its later history excluded from membership of the Irish parliament. Parliament in the eighteenth century met in a new, purposely designed parliament house (the first purposely designed two chamber parliament house in world history) in College Green in the heart of Dublin.

Many of these restrictions were repealed in 1782, allowing what came to be known as the Constitution of 1782. Parliament in this period came to be known as Grattan's Parliament, after one of the principal Irish political opposition leaders of the period, Henry Grattan.

By an Act of the Irish Parliament passed in 1800, the Kingdom of Ireland merged in 1801 with the Kingdom of Great Britain to form the United Kingdom of Great Britain and Ireland. The Irish Parliament ceased to exist, though the executive, presided over by the Lord Lieutenant, remained in place right up to 1922.

In 1922, the twenty-six southern counties that formed the Irish Free State left the United Kingdom. Under the Irish Free State Constitution, the King became King in Ireland. This was however changed fundamentally under the Royal Titles Act, 1927, by which the King explicitly became king of all his dominions in their own right, becoming fully King of Ireland instead. Though Kevin O'Higgins, Vice-President of the Executive Council (ie, deputy prime minister), did suggest resurrecting the 'Kingdom of Ireland' as a dual monarchy to link Northern Ireland and the Irish Free State, with the King of Ireland being formally crowned in a public ceremony in the Phoenix Park in Dublin, the idea was abandoned after O'Higgins' death in 1927.