Mr Sadleir commenced as the First Assistant Secretary, International Security Division at the Department of Foreign Affairs and Trade (DFAT) in April 2016.

His previous positions include service as First Assistant Secretary, National Security Division at the Department of the Prime Minister and Cabinet (PM&C), and various Senior Executive Service roles in PM&C, the Department of Foreign Affairs and Trade, the Attorney-General’s Department and the Department of Defence.

Overseas, Mr Sadleir has served in the Australian High Commission in Wellington (1995-1996) and the Australian Embassy in Washington DC (1998-2001).

Educated at the University of New South Wales, Mr Sadleir holds degrees in law and political science.