FK Radnički Sombor was founded in 1912 as Somborski Sport Klub, often abrviated to Somborski SK or sometimes also known as Sport Sombor. As the city was still within Austro-Hungary at that time, the club competed as Zombori Munkás TE in the Hungarian league system until 1914. During the First World War all football leagues were stopped, and only friendly matches took place. In 1918 Sombor became part of the Kingdom of Yugoslavia and the club played within the Subotica Subassociation League. The club archeved major success in 1924 when they managed to play in the Yugoslav First League which was played in a cup system. The club would not exist today if it was not the financial support they received from their sponsors during that time. One of the most entertaining games of the 1940s was in 1945 between Radnički Sombor and Radnički Belgrade; Radnički Sombor won the match 4–1. Their first season of professional league competition was disappointing, with only three wins in ten matches. In the 1952-53 season Radnički Sombor finished second behind FK Dinamo Pančevo. In 1954 in the Vojvodina First League (national 3rd tier) Radnički Sombor finished first; out of 88 games they won 47, drew 12, and lost 29. In the 1957-58 season they reaching the quarter-final in the Yugoslav Cup, where they lost to HNK Hajduk Split.
During the 1960s the club was promoted into the Yugoslav Second League. The stadiums were always packed, with tickets sold out a few days before the matches. Their fortunes again changed and they were moved out of the second tier and the club experienced financial troubles. In the 1971-72 season Radnički was back in the Vojvodina Provincial League. For the next ten years the club had very little success until the 1985/86 season, when they finished at the top of the league. In 1991/92 the club competed in the Inter-republics League North. Between 2009 and 2012 they were competing in second national level, the Serbian First League, but at the end of the 2011-12 season they were relegated to the Serbian League Vojvodina.