Íþróttafélagið Leiftur, from Ólafsfjörður, having spent most of their history in the lower leagues, were promoted to the Úrvalsdeild karla for the 1988 season, but went straight back down to the 1. deild karla. They were promoted again in 1994 to the top league for the 1995 Úrvalsdeild season having missed out by a point in 1993. Leiftur finished 5th in the Úrvalsdeild in their first season, finishing in 3rd the next two seasons, having some European adventures. In 1998 they finished 5th, but were runners-up in the cup to ÍBV who won the league, qualifying the team for the UEFA Cup 1999-00. The team lost to RSC Anderlecht 9–1 on aggregate in the first round, but managed to finish third for the third time in four years, qualifying them for a fourth season of European football. The year after, in 2000, the team was relegated from the Úrvalsdeild. After a mid-table finish in the 1.deild in 2001, the team merged with the club of neighbouring town Dalvík to become Leiftur/Dalvík, but this did not lead to success on the pitch as the team was relegated into the third tier of Icelandic football in 2003, and to the fourth tier in 2005. After that season Leiftur left the merger and merged with the team of another neighbouring town, Siglufjörður's Knattspyrnufélag Siglufjarðar, KS for short, to remain in the third tier, KS becoming KS/Leiftur. KS had previously had a few seasons in the second tier and produced future international players, but the most recent seasons in the second tier were not successful, with the club mostly staying in the third tier. Their last season in the second tier was a single season in 2005, merging with Leiftur after the season for the 2006 2. deild karla. Their best result in the second tier was a 3rd place in 1984 and a 4th place in 1985. KS/Leiftur didn't start the merger well, finishing 8th out of 10 in 2006, with the team finishing 10th being relegated, though KS/Leiftur never were in much danger of being relegated due to the relegated teams taking very few points. The next season went better, with the team finishing 3rd and being promoted as an extra team because of the expansion of teams in the top three leagues. Their 2008 season in 1. deild karla didn't go too well though, as the team only got 12 points from 22 matches, winning once and drawing nine times, finishing 12 points from safety. After finishing 8th and 9th in the 2. deild, the club took the next step and changed its name from KS/Leiftur to the united Knattspyrnufélag Fjallabyggðar, KF. Soon after the clubs of KS and Leiftur merged, their respective towns did effectively the same thing. The towns are connected with a tunnel through a mountain, a mountain that previously made travel between the towns much harder. So on 11 June 2006 Siglufjörður and Ólafsfjörður merged and the municipality of Fjallabyggð was created. Before the 2011 season, KS/Leiftur changed its name to Knattspyrnufélag Fjallabyggðar, KF for short, and hired former international Lárus Orri Sigurðsson as manager. The team finished 6th after a very close season, where 10 teams out of 12 had a chance of promotion for most of the season. In the 2012 season the club got promoted to the 2013 1. deild karla.
Current squad
Former players
Internationally capped and fully professional players
