On 25 January 2026, the Prime Minister recommended to the Governor-General that Mr Greg Moriarty AO be Australia’s next Ambassador to the United States of America. 

Mr Moriarty most recently served as Secretary of the Department of Defence (2017–2026), and was appointed and reappointed to the role by successive Australian governments. Mr Moriarty has held senior roles in the Prime Minister's office, first as the International and National Security Adviser and then as Chief of Staff to Prime Minister Malcolm Turnbull. In June 2015 Mr Moriarty was appointed Commonwealth Counter Terrorism Coordinator in the Department of the Prime Minister and Cabinet, responsible for coordinating and implementing Australia's counter terrorism arrangements in close partnership with State and Territory governments. 

Mr Moriarty has extensive diplomatic experience, including as Deputy Secretary of the Department of Foreign Affairs and Trade (2015), Ambassador to Indonesia (2010-2014), Ambassador to Iran (2005-2008) and as the Senior Negotiator with the Peace Monitoring Group on Bougainville. He has also had a long association with the Department of Defence, where he worked from 1986 to 1995 primarily in the Defence Intelligence Organisation. 

Mr Moriarty served in the Headquarters of the United States Central Command in the Persian Gulf during Operations Desert Shield and Desert Storm.

Mr Moriarty holds a Bachelor of Arts Degree with Honours from the University of Western Australia and a Master’s degree in Strategic and Defence Studies from the Australian National University. He is married with 2 children. He has studied Indonesian and Tok Pisin.