The Chief of Staff of the Defence Forces (COS) (Irish: Ceann Foirne na bhFórsaí Cosanta) 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 holds the rank of Lieutenant General and is assigned authority and responsibility by the Minister of Defence in respect of all staff duties connected with the executive management of the Defence Forces.

The Chief of Staff Lieutenant General Seán Clancy is the Defence Forces Chief of Staff with effect from 29th of September 2021. Lieutenant General Seán Clancy joined the Irish Defence Forces in 1984 as a cadet and commenced his flight training in 1986.

Major General Adrian Ó Murchú is the Defence Forces Deputy Chief of Staff (Support) with effect from 29th of September 2021, having been appointed by the government.

Lieutenant General Seán Clancy is an Irish Air Corps general and current Chief of Staff of the Irish Defence Forces since 29 September 2021. On 15 May 2024 it was announced that he would be the next chair of the European Union Military Committee (EUMC) with the rank of general.

Jul 13, 2021 · Major General Seán Clancy has been appointed as the new chief of staff of the Irish Defence Forces, succeeding Vice Admiral Mark Mellett, who will retire from this position September 29.

Jul 13, 2021 · Major General Seán Clancy has been appointed the next Chief of Staff of the Defence Forces and will take up the position after the retirement of Vice Admiral Mark Mellett on 29 September.

Lt Gen Seán Clancy has 37 years’ service in the Irish Defence Forces. He is the first Airman in the Irish State to serve as Chief of Staff, having previously served as Deputy Chief of Staff (Support) and General Officer Commanding Irish Air Corps and Director of Military Aviation.

President Higgins recieved the new Chief of Staff of the Irish Defence Forces, Lieutenant General Seán Clancy, at Áras an Uachtaráin. Lt Gen Clancy, whose appointment took effect on 29 September 2021, has 37 years’ service in the Irish Defence Forces.