Australia A-League

A national round-robin tournament existed in various forms prior to the formation of the A-League, with the most notable being the National Soccer League (NSL). The formation of the NSL came after Australia's qualification for the 1974 FIFA World Cup, which led to discussion of a national league, with 14 teams eventually chosen to participate in the inaugural season of the NSL in 1977.

Under the guidance of the then-governing body, the Australian Soccer Federation (later Soccer Australia), the NSL flourished through the 1980s and early 1990s but then fell into decline with the increasing departure of Australian players to overseas leagues, a disastrous television deal with the Seven Network and the resulting lack of sponsorship. Few clubs continued to grow with Sydney Olympic, Perth Glory, and the newly established Adelaide United the exception in a dying league.

In April 2003, the Australian Federal Government initiated the Independent Soccer Review Committee to investigate the governance and management of the sport in Australia, including that of the NSL. In December 2003, the Crawford Report found that the NSL was financially unviable, and in response the chairman of the sports new governing body, Frank Lowy of the Football Federation Australia, announced that a task force would be formed to create a new national competition as a successor to the NSL which dissolved at the conclusion of the 2003–04 season after 27 years of operation.

The A-League was announced in April 2004, as a successor to the NSL. Eight teams would be part of the new national competition, with one team from each city of Sydney, Melbourne, Brisbane, Adelaide, Perth, Newcastle, plus a New Zealand team and one from a remaining expressions of interest from either Melbourne or Sydney. The competition start date was set for August 2005.

By June of that year, 20 submissions had been received and a month later 12 consortiums sent in their final bids for the eight spots. Three bids were received from Melbourne, two each from Sydney and Brisbane, one from each of the remaining preferred cities and a bid from the New South Wales Central Coast city of Gosford. Over the next three months, each bid was reviewed and on 1 November 2004, the eight successful bidders and the major sponsor were revealed, for what would be known as the Hyundai A-League, with the Hyundai Motor Company unveiled as the official naming rights sponsor for the league.

The eight founding teams for the league were Adelaide United, the Central Coast Mariners, the Melbourne Victory, the Newcastle Jets, the New Zealand Knights, the Perth Glory, the Queensland Roar, and Sydney FC, with four former NSL clubs taking part, those being Adelaide United, the Newcastle Jets, and the Perth Glory, as well as the Queensland Lions who withdrew their first team from the Queensland State League and entered it in to the competition as the Queensland Roar plus the New Zealand Knights who were formed from the New Zealand Football Kingz. Each club was given a five-year exclusivity deal in its own market as part of the league's "one-city, one-team" policy. This was intended to allow clubs to grow and develop an identity in their respective region without local competition.

On 26 August 2005, 16 months after the demise of the NSL, the inaugural season of the A-League began. The first season would see Adelaide United win the premier's plate by seven points over Sydney FC with Central Coast and Newcastle filling the final two spots in the final series. In the final series, it was Sydney that took out the title after they defeated Central Coast by a Steve Corica goal to claim the first title on 5 March 2006. The following season saw Melbourne Victory claim the A-League premiers plate when they smashed Adelaide United 6–0 in the final at the Telstra Dome with Archie Thompson scoring five goals in the rout. But the season wasn't without a change with the New Zealand Knights being replaced by the Wellington Phoenix after the Knights were taken over by New Zealand Football after the team only won six times in forty-two games and selected overseas talent instead of local.

Both Gold Coast United and the North Queensland Fury joined the league in the 2009–10 season. On 12 June 2009, Melbourne Heart was awarded a licence to join the 2010–11 season. On 1 March 2011 North Queensland Fury's A-League licence was revoked for financial reasons. On 29 February 2012, Gold Coast United also had its licence revoked. On 4 April 2012, it was announced that a new Western Sydney-based club, Western Sydney Wanderers, would join the league for the 2012–13 season. In January 2014, Melbourne Heart was acquired by the City Football Group and was renamed Melbourne City ahead of the 2014–15 season. In February 2018, officials announced that the league would expand to 12 teams for the 2019–20 season. Later that year, the league announced that Western United FC would join the competition in 2019–20 and Macarthur would enter the following season (2020–21).

In the lead-up to the expansion announcements in 2019, club stakeholders entered into discussions with Football Federation Australia (FFA) to take over ownership of the competition. The league had been created and operated by the FFA since its inception in 2004, though by 2018 the FFA and clubs were at loggerheads over the permanent ownership structure of the league. A FIFA-backed congress review working group issued a sweeping 100-page report in August 2018, recommending an expanded domestic congress and an independent A-League, controlled and operated by the clubs. On 1 July 2019, the FFA and Australian Professional Football Clubs Association (the body representing the A-League clubs) announced an agreement had been reached for the FFA to relinquish control of the league to the clubs by the following month, in time for the start of the 2019–20 season. The agreement brought the sport in line with the governance structure utilised in most European leagues. The new ownership body is called the Australian Professional Leagues, a consortium of the A-League clubs and their owners, with certain rights held by the FFA, and a capital investment & ownership stake held by American firm Silver Lake. A-League officials in May 2021 announced that the league will align to the Domestic Match Calendar to avoid clashing with FIFA Days, as well as introducing Domestic Transfer System and National Club Licensing frameworks.