Knattspyrnudeild Keflavíkur, or Keflavík Football Club, was founded in the town of Reykjanesbær in 1929. The team have been a part of the Icelandic football league since 1956 and have enjoyed occasional success in the major domestic competitions throughout history. The football team is a subdivision of Keflavík ÍF, a sports club which also has basketball, gymnastics and swimming clubs.
After starting out in the country's second tier, Keflavík were able to gain promotion to the top flight, the Úrvalsdeild, in 1958. Their initial stay lasted two seasons, before they were relegated back to the second division. Since that time, they have bounced up and down between the first and second tiers on multiple occasions, with their most recent promotion coming at the end of the 2003 season.
The club experienced its golden era in the 1960s and 1970s, during which time they won league titles in 1964, 1969, 1971 and 1973. In addition, Keflavík won their first Icelandic Cup in 1975. Although they have not yet been able to achieve the same level of succss, the team have won further honours, claiming an additional three Icelandic Cups in 1997, 2004 and 2006, in order to take their total number of cup wins up to four. As a result of their success in domestic competitions, Keflavík have participated in the European Cup, UEFA Cup and UEFA Cup Winners' Cup.
Guðmundur Steinarsson is the club's greatest ever goalscorer and their record appearance maker. In 2008 he was named as the Players' Player of the Year for the Úrvalsdeild. Other notable former players include Steinar Jóhannsson, Ragnar Margeirsson, Sigurður Björgvinsson and Óli Þór Magnússon.
Keflavík home games are played at Keflavíkurvöllur, which is also known as Nettó-völlur for sponsorship reasons. The venue was renovated in 2009 and is currently able to hold up to 4,000 supporters for football matches.