9 Chiefs of Staff of the Defence Forces (Ireland)

The Chief of Staff of the Defence Forces (COS) is charged with the executive management of the Irish Defence Forces, and is the most senior military officer of the Army, Naval Service and Air Corps branches. The Chief of Staff is appointed by the President of Ireland, who is the Supreme Commander of the Defence Forces, on the recommendation of the Minister for Defence subject to the approval of the Government of Ireland. The office of the Chief of Staff consists of his personal staff, a strategic planning office and a public relations section.

Lieutenant-General Dermot Earley DSM was a high-ranking military official in Ireland and with the United Nations. He was the Chief of Staff of the Defence Forces from 2007 to 2010.

Seán Mac Eoin was an Irish Fine Gael politician and soldier who served as Minister for Defence briefly in 1951 and from 1954 to 1957, Minister for Justice from 1948 to 1951, and Chief of Staff of the Defence Forces from February 1929 to October 1929. He served as a Teachta Dála (TD) from 1921 to 1923, 1929 to 1957, and 1961 to 1965.

Lieutenant General Sean McCann was the Chief of Staff of the Defence Forces from 9 June 2010 until his retirement on 12 August 2013. He assumed command in 2010 upon the retirement of Lieutenant General Dermot Earley, DSM.

Vice Admiral Mark Mellett, DSM, is an Irish Naval Service admiral and the current Chief of Staff of Ireland's Defence Forces since September 2015.

Richard James Mulcahy was an Irish Fine Gael politician and army general who served as Minister for Education from 1948 to 1951 and from 1954 to 1957, Minister for the Gaeltacht from June 1956 to October 1956, Leader of the Opposition from 1944 to 1948, Leader of Fine Gael from 1944 to 1959, Minister for Local Government and Public Health from 1927 to 1932 and Minister for Defence from January to April 1919 and from 1922 to 1924. He served as a Teachta Dála (TD) from 1918 to 1938 and from 1943 to 1961.

Lieutenant General Conor O'Boyle was the Chief of Staff of the Irish Defence Forces from August 2013 until September 2015. O'Boyle was appointed to the post by the Government of Ireland on 12 August 2013. O’Boyle joined the Defence Forces in 1970 and was assigned to the Artillery Corps upon his commission in 1972. O'Boyle served in Middle East for two years with UNTSO and has been on three tours of duty with UNIFIL.

Eoin O'Duffy was a fascist Irish nationalist political activist, soldier and police commissioner. He was the leader of the Monaghan Brigade of the Irish Republican Army (IRA) and a prominent figure in the Ulster IRA during the Irish War of Independence. In this capacity he became Chief of Staff of the IRA in 1922. He accepted the Anglo-Irish Treaty and served as a general in the National Army in the Irish Civil War, on the pro-Treaty side.

Lt. General James Sreenan is a former Chief of Staff of the Defence Forces.