The history of the Australian Greens has its origins in the green parties founded in the 1980s in each of the states of Australia.

Formation The formation of the Australian Greens in 1992 brought together over a dozen green groups, from state and local organisations, some of which had existed for 20 years.

The precursor to the Tasmanian Greens (the earliest existent member of the federation of parties that is the Australian Greens), the United Tasmania Group, was founded in 1972 to oppose the construction of new dams to flood Lake Pedder. The campaign failed to prevent the flooding of Lake Pedder and the party failed to gain political representation. One of the party's candidates was Bob Brown, then a doctor in Launceston.Senator Bob Brown – Australian Greens www.bobbrown.org.au (PDF file)

In the late 1970s and 1980s, a public campaign to prevent the construction of the Franklin Dam in Tasmania saw environmentalist and activist Norm Sanders elected to the Tasmanian House of Assembly as an Australian Democrat. Brown, then director of the Wilderness Society, contested the election as an independent, but failed to win a seat.Results in Denison for the election held on 15 May 1982, Tasmanian Parliamentary Library

In 1982 Norm Sanders resigned from the THA, and Brown was elected to replace him in a countback, which involves re-counting the ballots from the election that elected the incumbent to elect one of the candidates who stood but failed to be elected in the same election.

During her 1984 visit to Australia, West German Greens parliamentarian Petra Kelly urged that the various Greens groups in Australia develop a national identity. Partly as a result of this, 50 Greens activists gathered in Tasmania in December to organise a national conference.About us – The Greens , www.greens.org.au

The title "The Greens" had been first registered in Sydney in the 1980s by what The Monthly Magazine described as "a band of inner-city radicals committed to resident action, nuclear disarmament and urban environmental causes, such as stopping expressways and preserving parklands". The group formed as the Sydney Greens and evolved into the Green Alliance, with the stated aim of not forming a "traditional hierarchy party". According to party co-ordinator Hall Greenland, when amalgamation with Bob Brown's Tasmanian movement was first mooted, Brown was hesitant owing to what he perceived as the "anarchic leftism" of the Sydney movement. The Greens NSW and The Greens (WA) were also wary of amalgamation owing to local autonomy concerns and a 1986 attempt by Brown to form a national party failed. However, Drew Hutton, a founder of the Queensland Greens in 1990, was a driving force for the national party's formation and the movement continued. In an effort to reduce the influence of the Democratic Socialist Party (formerly Socialist Workers Party, now Socialist Alliance) in The Greens NSW, Brown successfully moved for a ban on dual party membership by Greens in 1991. Following formation of the national party in 1992, regional emphasis variations remained within the Greens, with members of the "industrial left" remaining a presence in the New South Wales branch.

The Green movement gained its first federal parliamentary representative when Senator Jo Vallentine of Western Australia, who had been elected in 1984 for the Nuclear Disarmament Party and later sat as an independent, was part of the formation of and joined The Greens (WA), a party formed in Western Australia, and not affiliated to the Australian Greens at that time.

In 1992, representatives from around the nation gathered in North Sydney and agreed to form the Australian Greens, although the state Greens parties, particularly in Western Australia, retained their separate identities for a period. Brown resigned from the Tasmanian Parliament in 1993, and in 1996 he was elected as a senator for Tasmania, the first elected as an Australian Greens candidate.

Initially the most successful Greens group during this period was The Greens (WA), at that time still a separate organisation from the Australian Greens. Vallentine was succeeded by Christabel Chamarette in 1992, and she was joined by Dee Margetts in 1993. But Chamarette was defeated in the 1996 federal election. Margetts opposed the industrial relations reform agenda of the Howard government. Following the 'Cavalcade to Canberra' protest of 19 August 1996, in which 2000 breakaway civilians rioted in and around Parliament House,Luke Deer The Parliament House riot of 1996. Retrieved 13 May 2012. Margetts told the Senate that "The Greens (WA) do not associate ourselves with the violent action" and that while "there are obviously some in the Greens movement who have differing opinions about that" she personally did not think there was "any justification for the use of violence to the extent that we saw". Margetts lost her seat in the 1998 federal election, leaving Brown as the sole Australian Greens senator.

Leadership of Bob Brown

The national party initially resisted appointing a party leader, however Bob Brown was later selected. The New South Wales Greens remained ideologically opposed to appointing a leader and continue not to appoint such a position. The WA Greens had lost office in the Senate by 1998, leaving Bob Brown as the sole representative of the party. Thereafter, the national vote was set to increase consecutively at elections up until 2010.

2001 federal election onward In the 2001 federal election, Brown was re-elected as a senator for Tasmania, and a second Greens senator, Kerry Nettle, was elected in New South Wales. The Greens opposed the Howard government's Pacific Solution of offshore processing for asylum seekers, and opposed the bipartisan offers of support to the US alliance and Afghanistan War by the government and Beazley Opposition in the aftermath of the 11 September terrorist attacks in 2001, describing the Afghanistan commitment as "warmongering".Steve Letts PM explains Australian involvement in Afghan war . ABC Lateline, 25 October 2001. Retrieved 13 May 2012. This contributed to increased support for the Greens by disaffected Labor Party voters and helped identify the Greens as more than just a single-issue environmental party. On 19 October 2002 the Greens won a House of Representatives seat for the first time when Michael Organ won the Cunningham by-election.

In the lead-up to the Iraq War, in September 2002, Bob Brown said that the Greens would oppose military action in Iraq regardless of the position of the United Nations Security Council and said that any conflict would be "a vengeance for the S11 attack that's involved here as well as the American corporations wanting to get their hands on the Iraqi oil" and that if Saddam Hussein "does have weapons of mass destruction, the attack might be the thing that gets him to use them", so it would be better to "resolv[e] the Palestinian crisis, which could lead—open up a real avenue to peace in the Middle East, and neutralise Saddam Hussein by doing it".Tony Jones Call for Howard to meet with Hussein . ABC Lateline, 19 September 2002. Retrieved 13 May 2012.

2004 federal election onward In the 2004 federal election, the Greens' primary vote rose by 2.3% to 7.2%. This won them two additional Senate seats, taken by Christine Milne in Tasmania and Rachel Siewert in Western Australia, bringing the total to four. However, the success of the Howard government in winning a majority in the Senate meant that the Greens' influence on legislation decreased. Michael Organ was defeated by the Labor Party candidate in Cunningham.

Additionally, in the 2004 election there was an intense media campaign from the socially conservative Family First Party, including a television advertisement labelling the Greens the "Extreme Greens". Competitive preferencing strategies prompted by the nature of Senate balloting (see Australian electoral system) lead to the Australian Labor Party and the Democrats ranking Family First higher than the Greens on their Senate tickets, and the Greens losing preferences they would normally have received from the two parties. Consequently, although outpolling Family First by a ratio of more than four to one first-preference votes, Victorian Family First candidate Steve Fielding was elected on preferences over the Australian Greens' David Risstrom, an unintended consequence of these strategies."How party preferences picked Family First", The Age, 11 October 2004. In Tasmania, Christine Milne only narrowly gained her Senate seat before a Family First candidate, despite obtaining almost the full required quota of primary votes. It was only the high incidence of "below-the-line" voting in Tasmania that negated the effect of the preference-swap deal between Labor and Family First."Above or below the line? Managing preference votes", On Line Opinion, 20 April 2005

The Australian Greens fielded candidates in every House of Representatives seat in Australia, and for all state and territory Senate positions. The Greens (WA) were able to win Legislative Council seats in rural and remote-area seats (Mining and Pastoral, Agricultural and South West provinces).

In 2005, the Greens' Lee Rhiannon lobbied the Vatican to reject Australian Cardinal George Pell as a candidate for the Papacy on the basis of his support for conservative Catholic moral doctrine. In 2007, Rhiannon referred remarks made by Pell opposing embryonic stem cell research to the New South Wales parliamentary privileges committee for allegedly being in "contempt of parliament". Pell was cleared of the charge and described the move as a "clumsy attempt to curb religious freedom and freedom of speech".

The Australian Greens' primary vote increased by 4.1% in the 2006 South Australia election, 1.% in the 2006 Queensland election, and 0.7% in the 2007 election in New South Wales.

The results for the 2006 Victoria election were mixed, with an improved vote for the Greens in the lower house, but a fall in their upper-house vote.

Against this upward trend was a swing of 1.5% away from the Greens in the 2006 Tasmania state election."ABC Coverage of Australian Elections", Australian Broadcasting Corporation, 31 March 2007

On 31 August 2004, the Melbourne newspaper the Herald Sun published a page-three-story by journalist Gerard McManus entitled "Greens back illegal drugs" in the lead-up to the 2004 federal election. In response to the article, Brown lodged a complaint with the Australian Press Council. After the election, the Press Council upheld Brown's complaint. An appeal by the Herald Sun was dismissed and it was ordered to publish the Press Council's adjudication.Herald Sun Found Guilty of Irresponsible Journalism and Seriously Misleading Readers, Press Releases, Victorian Greens, 4 March 2005. (archived copy of page)

At the 2004 election, the Australian Greens would replace the Australian Democrats as the largest third party in elections. As of 2025 the Greens would be the largest third party.

2007 federal election onward

As in previous years, the Greens' vote was strongest in inner-city seats, including Melbourne (22.7% of primary votes), Sydney (20.7%), Grayndler (18.7%), Denison (18.6%) and Batman (17.2%). Strong votes were also recorded in Liberal-held city based seats such as Higgins (10.8%), Kooyong (11.8%) Curtin (13.4%) and Wentworth (15.0%). The primary vote for the Greens in suburban and regional areas was generally smaller.

The Greens directly contributed to Howard's defeat in his own electorate, the Sydney-area seat of Bennelong. Greens candidate Lindsay Peters received 5.5% of the primary vote. He was eliminated after the 14th count, and more than three-fourths of his preferences went to Labor challenger Maxine McKew. This margin was enough to make McKew only the second person to unseat a sitting prime minister.