Founded in 1983 as the 'Korea Professional Soccer League', the K-League as it is known today is the oldest professional league in Asia and is regarded as one of the strongest leagues on the continent. Five teams took part in the initial competition - Hallelujah, Daewoo, Yukong Elephants, POSCO and Kookmin Bank. The league toured the peninsula each matchday and at the end of the season Hallelujah ended up the inaugural champions.
The clubs were joined by three new members for 1984 with Hanil Bank, Hyundai Horang-i and Lucky-Goldstar all gaining membership. That season was to be Kookmin Bank's last in the top flight as the left the league, replaced by the military side Sangmu who joined for only one season before leaving at the end of 1985. The first ever champions Hallelujah also departed the league that season, turning amateur and dropping into the lower ranks. Hanil Bank left the K-League in 1986 and from eight teams the league had shrunk back down to five. POSCO Atoms were becoming a dominant force in the mid-1980s, and by 1989 Ilhwa Chunma had been admitted to the league bringing the membership up to six clubs.
By 1993 Ilhwa Chunma had lifted the first of what would be three successive titles, and in 1995 two southern teams, Cheonbuk Dinos and Chunnam Dragons, gained membership. The Dinos were admitted to the league to replace the ill-fated Chonbuk Buffalo who competed for the 1994 season before folding after a poor season with only three wins from 30 games.
1996 saw Suwon Samsung Bluewings swell the membership to nine clubs, and was also the year when 'localism' took over in the K-League and the corporate clubs all adpoted their local identities within club names. Daejeon Citizen, the first publicly funded professional club in Korea, joined the league in 1997 as the league began a drive to expand the professional setup in advance of the hosting of the 2002 World Cup.
Buoyed by the success of the World Cup tournament, the league expanded to 12 clubs in 2003 with the readmission of Sangmu, based in Gwangju, and also the newly created Daegu FC. Incheon United joined in 2004 to bring the membership up to thirteen, and the entry of Gyeongnam FC for the 2006 season brought the complement up to the 14 of the present day.