A Department of External Affairs was first established on 1 January 1901, but it only lasted till 1916 when it was abolished and most of its functions passed to the Prime Minister's Department (CA 12).

The Department of External Affairs [II] was created on 21 December 1921. (1) 

During the first fourteen years of its existence the Department was linked administratively to Prime Minister's Department, the Secretary to the Prime Minister's Department acting also as the Secretary to the Department of External Affairs [II].
 
The Department of External Affairs [II] was originally created to deal with Australia's relations with the League of Nations and other general matters. 

In 1924, following the Imperial Conference of 1923, which very fully discussed the foreign policy of the British Commonwealth, the Department was reorganised. Allan Leeper, an Australian-born member of the British Diplomatic Service, was loaned to the Australian Government by arrangement with the Foreign Office for six months to advise on establishing the Australian Department. (2)
 
The first Administrative Arrangements Order which lists the functions dealt with by the Department as an entity and not in conjunction with Prime Minister's Department (that of 14 April 1932) lists the following:  

. Consuls and Consular matters;
. Foreign Affairs;
. Foreign Intelligence;
. Foreign Press;
. International Conferences;
. League of Nations (including International Labour Organization and 
  Permanent Court of International Justice); and
. Treaties. (3)
 
In 1935, the Department of External Affairs [II] was separated administratively from the Prime Minister's Department and Lt Col W R Hodgson was appointed as Secretary of the Department.

The Department was divided into two main parts, the Political Section and the International Co-operation Section. (4)  

It continued to develop gradually until the outbreak of war in September 1939 but, from then on, its work and responsibilities increased rapidly.

The greatest increase in the responsibility of the Department arose as a result of Australia's representation in other countries and on international organizations. 

Prior to 1940, Australia had not adopted the practice of appointing her own Ministers or consular representatives to foreign countries and relied on a limited system of liaison. Except for the High Commission in London (which reported to the Prime Minister's Department), Australia only maintained liaison officers in London, Tokyo and Washington. However, Australia's diplomatic representation had to be reconsidered under the pressure of a deepening world crisis and a legation, headed by a Minister (Mr Casey) was established in Washington in February 1940. This was followed in March by the establishment of a High Commission in Canada and in December by the appointment of a Minister in Tokyo (Sir John Latham).
 
Australia's first Minister to China, Sir Frederic Eggleston, was appointed in October 1941. Between 1940 and 1945, Australia appointed official representatives in New Caledonia, Singapore, USSR, New Zealand, India and France.
 
The Second World War also stimulated considerable development in the establishment of the Department in Canberra. A Communications and Records Section was established in October 1939 and a Cables Section was set up by December 1940 to handle the increase in cable traffic. The Department assumed responsibility for the conduct of political warfare against Japan in mid 1942 and a Political Warfare Section was established.
 
In January 1943, the Minister for External Affairs, Dr H V Evatt, introduced the External Affairs cadet scheme designed to train officers for the diplomatic corps.

In May 1943, the Cables Branch of the Prime Minister's Department merged with the Cables Section of External Affairs to form the External Communications Branch of External Affairs, with the responsibility for all governmental cablegrams to or from Australia.
 
In the same month, a Post-War Reconstruction Section under the direction of Mr Hasluck, was set up within the Department to undertake a general study of all economic questions which came before the Department as well as the handling of such matters as the currency stabilization plans, post-war commercial policy, relief and
rehabilitation, the decisions of the Hot Springs Food Conference and trade negotiations.
 
During 1944, the internal organization of the Department developed considerably. A Pacific Affairs Division and an Intelligence and Information Division were formed. In July of that year, the Post-War Reconstruction Division was converted into the Post Hostilities Division, to deal with questions relating to the armistice and peace settlements. In November that same year, a European and Middle Eastern Division was formed followed, in December, by the formation of an Economic Relations Division.  

In the immediate post-war period there was a further increase in departmental responsibility as new missions were opened and others were raised in status and Australia participated in the activities of various international organizations. (5)
 
In 1963, the Department gained control of the International Training Centre from Prime Minister's Department and lost the Antarctic Division to the Department of Supply in 1968. (6)
 
By 1970, the functions of the Department of External Affairs [II] were broadly described as covering foreign affairs and relations with overseas governments, including Commonwealth relations. (7)  It was responsible for the protection of Australian interests and Australian citizens abroad and for the dissemination of information and intelligence relating to international affairs as well advising the Government on foregin policy, including those aspects of it which arise in the field of defence, trade and administration of Australian territories overseas. 

The Department, by this time, was also responsible for:
 
(a) control of Australian Embassies, Legations, High Commissions, 
    Consulates and similar permanent missions abroad having
    diplomatic status and within Australia for relationships
    between the Australian Government and foreign diplomatic
    missions and consulates;
 
(b) all communications, including telegraphic traffic, between the 
    Australian Government and other Governments and the Diplomatic 
    Mail Service and the Safe Hand Mail Service;
 
(c) advising on Australian policy or matters that arise in the
    various organs of the United Nations and the specialised
    agencies associated with the United Nations and with the
    International Atomic Energy Agency, these matters including,
    apart from purely political issues, questions of trusteeship,
    international economic and cultural relations;
 
(d) implementation of the Australia-New Zealand Agreement, the 
    security treaty between Australia, New Zealand and the United 
    States and the foreign policy aspects of Australian
    participation in South East Asia Collective Defence Treaty;
 
(e) the administration of external aid policy (excluding the
    Territory of Papua and New Guinea), Australian aid programmes 
    under the Colombo Plan, the Special Commonwealth Assistance to
    Africa Programme, the Australian South Pacific Aid Programme, the
    South East Asian Treaty Organization, the Australian  
    International Award scheme and other programmes as well as the 
    welfare of overseas students in Australia;
 
(f) Australian policy in respect of the South Pacific Commission;  

(g) general questions of international law (in consultation with the
    Attorney-General's Department), relations with the International
    Court of Justice, the International Law Commission, negotiation
    and conclusion of treaties and international agreements, 
    publications of the Australian Treaty Series and maintenance of 
    the Australian Treaty Series and maintenance of the Australian 
    Treaty List; and
 
(h) advising on matters relating to Australia's cultural relations  
    with other governments and for co-ordinating and implementing
    the works of other agencies of government and non-government
    bodies in the external cultural relations field.
 
On 6 November 1970, the Department of External Affairs [II] was renamed the Department of Foreign Affairs (CA 1382) by Executive Council Meeting No 18 (Prime Minister's Minute No 45) and took over all of its predecessor's functions. (8)
 
The following had been Ministers for External Affairs [II]:
 
21 Dec 1921 -  9 Feb 1923  : Hon William Morris Hughes (CP 290)
 9 Feb 1923 - 22 Oct 1929  : Hon Stanley Melbourne Bruce (CP 28)
22 Oct 1929 -  6 Jan 1932  : Hon James Henry Scullin (CP 63)
 6 Jan 1932 - 12 Oct 1934  : Hon John Greig Latham (CP 143)
12 Oct 1934 - 29 Nov 1937  : Senator the Hon Sir George Foster Pearce
                             (CP 151)
29 Nov 1937 - 26 Apr 1939  : Hon William Morris Hughes (CP 290)
26 Apr 1939 - 14 Mar 1940  : Hon Sir Henry Somer Gullett
14 Mar 1940 - 28 Oct 1940  : Hon John McEwen (CP 47)
28 Oct 1940 -  7 Oct 1941  : Hon Sir Frederick Harold Stewart
 7 Oct 1941 - 19 Dec 1949  : Hon Herbert Vere Evatt (CP 7)
19 Dec 1949 - 27 Apr 1951  : Hon Percy Claude Spender
27 Apr 1951 -  4 Feb 1960  : Hon Richard Gardiner Casey (CP 24)
 4 Feb 1960 - 22 Dec 1961  : Hon Robert Gordon Menzies (CP 54)
22 Dec 1961 - 24 Apr 1964  : Hon Sir Garfield Edward John Barwick 
24 Apr 1964 - 11 Feb 1969  : Hon Paul Meernaa Caedwalla Hasluck 
                             (CP 115) 
11 Feb 1969 - 12 Nov 1969  : Hon Gordon Freeth (CP 45)
12 Nov 1969 -  6 Nov 1970  : Hon William McMahon
 
From its creation until the appointment of Lt Col W R Hodgson, CMG, OBE, the Secretary of the Department was the Secretary of
Prime Minister's Department. After the administrative separation of the Department of External Affairs [II] in 1935 the following held the position of Secretary:
 
19 Nov 1935 - 21 Jun 1945  : Lt Col W R Hodgson, CMG, OBE (CP 80) 
10 Sep 1945 - 25 Mar 1947  : Sir William E Dunk, CBE
27 Mar 1947 - 17 Jun 1950  : Dr J W Burton
19 Jun 1950 - 24 Jan 1954  : Sir Alan S Watt, CBE (CP 951)
25 Jan 1954 -  4 Apr 1965  : Sir Arthur Tange, CBE (CP 229)
 5 Apr 1965 -    Apr 1970  : Sir James Plimsoll, CBE (CP 452)
 6 Apr 1970 -  5 Nov 1970  : Sir Keith Waller, CBE (CP 950)
 
Sources:
 
1. Commonwealth of Australia Gazette, No 99, 24 December 1921, p 2403 2. Department of External Affairs [II], Correspondence files,
   multiple  number series with year and letter prefixes, 1945:
   History of the  Department. Australian Archives: CRS A1067, PI46/9/1
3. Commonwealth of Australia Gazette, No 35, 14 April 1932, p 547 
4. Department of External Affairs [II] , Correspondence files,
   multiple  number series with year and letter prefixes, 1945:
   History of the Department. Australian Archives: CRS A1066, PI
   46/9/1
5. Neale, R G (ed) Documents on Australian Foreign Policy 1937-1949, 
   Vol 1, Australian Government Publishing Service, Canberra, 1975, 
   pp 546-554
6. Commonwealth of Australia Gazette, No 55, 20 June 1968, p 3370 
7. Commonwealth Directory, 1970, p 84
8. Commonwealth of Australia Gazette, No 98, 6 November 1970, p 7507

Historical agency address

  1921-by1926 : Commonwealth Offices, Treasury Gardens, Melbourne
by1926-  1956 : Commonwealth Offices, West Block, Canberra
by1956-  1970 : Administrative Building, Parkes, Canberra, ACT

Legislation administered

Creation: Executive Council Meeting No 70 (PM's Minute No 316) of 21 December 1921
Abolition: Executive Council Meeting No 18 (PM's Minute No 45) of 6 November 1970