During this time, Australia's overseas activities were predominantly related to trade and commercial interests, while its external affairs were concerned mostly with immigration, exploration and publicity.

[7] The political and economic changes wrought by the Great Depression and Second World War, and the adoption of the 1931 Statute of Westminster (ratified by Australia in 1942), necessitated the establishment and expansion of Australian representation overseas, independent of the United Kingdom Foreign Office.

The functions of the department are broadly classified into the following matters as laid out in an Administrative Arrangements Order issued on 18 September 2013:[12][needs update] Four additional ministers support the Minister for Foreign Affairs in administering the Department, as of 2022[update]:[13] DFAT is administered by a senior executive, comprising a secretary and five deputy secretaries.

LES are citizens of the country in which the relevant DFAT Post is located, providing invaluable administrative and policy support to Australian officers whilst they conduct their overseas duties.

Additionally, the department manages a network of 116 overseas posts, including Australian embassies, high commissions and consulates-general.