Secretary of Defence

Welcome

Duncan Lewis is the Secretary of the Department of Defence. Building on almost four decades of experience in the defence and national security communities, he commenced in this role on 5 September 2011.

Born in 1953, Duncan joined the Australian Army after schooling in Western Australia, graduating from the Royal Military College, Duntroon in 1975. A career in the military, spanning 33 years, followed. During this time Duncan commenced in the Special Air Service Regiment and rose to the rank of Major General. He was awarded the Conspicuous Service Cross for his service in East Timor and appointed as an Officer of the Order of Australia for his service in command of Australian Special Forces.

In 2005, Duncan left the military and joined the public service. His initial appointment was as First Assistant Secretary of the National Security Division within the Department of Prime Minister and Cabinet. Later that year, he was promoted to Deputy Secretary and shortly after, he was appointed as an Associate Secretary. Here he led the National Security and International Policy Group and contributed to the Department’s broader leadership as a member of its Executive. He served as the Chair of the Board of the National Security College and as an ex officio member of the Council of the Order of Australia and the National Australia Day Committee.

From December 2008, Duncan served as Australia’s inaugural National Security Adviser. Duncan was the Prime Minister’s principal source of advice on all national security matters. He had responsibility for the strategic leadership of the national security community, as well as the coordination of national security policy development and crisis response.

Duncan is a graduate of the British Army Staff College, Camberley and the United States Army War College. He holds a Bachelor of Arts degree from the University of NSW and a Graduate Diploma in Defence Studies and Management from Deakin University. He is fluent in Indonesian.

Duncan is married to Jenny, and they have two children, Simon and Alison. His interests include classical music, history, Australian Rules football and tennis.