The Australian Journalists' Association (AJA) was formed in Melbourne on 10 December 1910 and registered under the Commonwealth Conciliation and Arbitration Act on 23 May 1911. The New South Wales Branch (then District) of the Union was formed on 25 August 1911, having taken over the assets and liabilities of the New South Wales Institute of Journalists which had been formed a few years prior in 1907 as a statewide association of press reporters. In 1913 the AJA NSW District was registered under the Trades Union Act of NSW, later adopting the title of NSW Journalists' Union for the purposes of state arbitration.

On 11 May 1913 The Writers' and Artists' Union amalgamated with the NSW District. An Authors' Section of the NSW District was established in August 1921 to protect the interests of Australian authors and in particular to act against the importation into Australia of syndicated literary material. The Section lapsed in 1926 and was reconstructed in 1935 as the Authors' and Artists' Section. The AJA NSW District Ethics Committee was formed on 7 July 1942 to prepare and administer a Code of Ethics which was adopted in August 1942. The Code bound all members of the NSW District to standards of professional conduct and the Ethics Committee continued its operations through the 1960s and 1970s as the Judiciary Committee.

The AJA NSW Benevolent Fund was established by the NSW Institute of Journalists, handed over to the AJA NSW District in 1911 and later received substantial support from J. F. Archibald, founding editor of The Bulletin. The fund operates to provide the financial assistance to journalists and their families affected by unemployment, sickness, incapacity or death. Since its establishment the AJA New South Wales Branch has sought to obtain award coverage of its members employed in newspapers, government departments, law courts and other organisations. In 1979 its members included journalists (including those employed in broadcasting and television), authors, shorthand writers, Hansard reporters, public relations officers, photographers and press artists.

The Australian Journalists Association is a federal union governed by a Federal Council meeting annually and consisting of an elected executive and two delegates (branch secretary and branch president) from each branch. Until 1968 Federal Executive Officers were elected by Federal Council after nominations by branch committees. Federal Executive Offices after 1969 were elected by a ballot of AJA membership. The AJA Federal Office was located in Melbourne from 1911-1932 and moved to Sydney in 1933. AJA Branch Committee members and Branch Officers were elected by Branch membership and served annual terms with the exception of the Branch secretary who since 1943 has served triennial terms. This union served its members until 1991 when it amalgamated with the Australian Commercial & Industrial Artists' Association to form a new reregistered Australian Journalists' Association. Between 1992 and 1993 the AJA amalgamated with the Australian Theatrical and Amusement Employees' Association and the Actors' Equity of Australia to form the Media Entertainment and Arts Alliance in 1993.