In the 1970s the top sides from Melbourne and Sydney played off in an end of season series,[10] but the tournament did not seem to quite capture the legitimacy and popularity that was hoped for.

Plans for a national home and away league went back as far as 1965 for a 1967 start,[11] and were followed up by variations on the theme throughout the 1960s and early 1970s, but faced opposition variously from clubs, who deemed the notion uneconomical, and state federations who feared losing their power.

Australia's qualification for the 1974 World Cup led to various discussions in 1975 and 1976, with eventually 14 teams being chosen to participate in the inaugural season of the national league.

Little-known Mooroolbark from Melbourne's outer eastern suburbs broke the deadlock by joining the competition, bringing three other Victorian sides with it, making the national league a reality.

[15] Shrinking crowds led to the radical move of introducing more teams (mainly from Victoria and New South Wales) and splitting the league into two conferences, with the winner of each division to play-off in an end of year two legged final.

This period saw South Melbourne become the first Victorian team to win the league, followed by Brunswick Juventus, and Adelaide City, all Southern conference sides.

At the end of the 1986 season, the system was scrapped, and about half the teams were dumped back to their respective state leagues.

The revamped league suffered a major setback early on when Sydney City pulled out of the competition after just one round into the new season.

This coincided with a renewed push by soccer authorities to force clubs to market themselves to mainstream Australia, as opposed to their own mostly migrant fan bases.

From 1996 onwards the league attempted to revitalise the competition and attempt to hook into the mainstream support by finally introducing a team from Western Australia, in the form of Perth Glory, as well as other new entities which promised to deliver mainstream support, as well as being fully professional outfits as opposed to the majority of clubs and players who were only semi-professional.

Collingwood Warriors barely managed to last a season, while Carlton reached the grand final in its debut year, but was unable to attract a substantial fan base.

Parramatta Power failed to gather much support, placed as it was in the midst of the already crowded western Sydney soccer market, and it too would not last beyond the end of the NSL.

High crowds and good performances throughout the NSL's last decade made Perth Glory for many observers the benchmark and role model for all future entrants to the Australian top-flight.

South Melbourne FC under Ange Postecoglou won back-to-back titles in the late 1990s, and by also winning the 1999 Oceania Club Championship, earning the right to play in the 2000 FIFA Club World Championship, where it put in some respectable performances against sides such as Manchester United and a tidy sum in prize money.

High-profile Australian players began to leave the NSL due to more enticing offers from overseas leagues.

In 1998, Soccer Australia sold the television rights for the NSL and Socceroos matches to the Seven Network in a 10-year contract that was worth $2.5 million a year.

The consequent lack of sponsorship meant the league fell into even further decline which led to its eventual demise at the end of the 2003–04 season.

The league in 2003–04 was won by Perth Glory after a 1–0 win against Parramatta Power on 4 April 2004, almost 27 years to the day that the national competition began.

In 1987, the league dumped 11 teams, scrapped the split divisions, and the championship system reverted to first past the post.