FC Zeleznik was founded in 1930 in Zeleznik, a Belgrade suburb. The club proceeded with more serious activities in 1952. FC Napredak was formed later on in the new Zeleznik settlement within "Ivo Lola Ribar" factory, originally under the name "The Red Machine". It was formed in 1948, the same year when the works on building the factory began. In 1961 Zeleznik and Napredak decided to unite in one club and keep the name of the older one. The new club was thus named FC Zeleznik from Zeleznik. After the war, Zeleznik had its senior and junior teams competing in Belgrade league. After the fusion in the period between 1962 and 1968 the first team proved successful in competitions on the territory of Belgrade Football Association and Serbian Football Association: winner of the Yugoslav Cup on Belgrade territory in 1963/64, winner of the Yugoslav People's Rising Cup in 1971. Zeleznik was champion of Belgrade in 1962/1963 and winner of the first sub-national league, division B in 1961/1962. Between 1963 and 1966 Zeleznik played in the Serbian League, North division. As champion of the Serbian League Zeleznik played FC Sloboda Uzice in the preliminary round to enter the Second National League, still failed to achieve that goal to the disappointment of its fans. In the same period, the junior teams competed in Belgrade leagues with variable success. In the period between 1972 and 1973, the club languished in Belgrade leagues (regional, municipal) and found itself in year 1991/1992 in the Belgrade zone league A, B, C, then seven ranks below the First National League. In the meantime, a new stadium was built and the club has been using it since 1981. At the end of the autumn season 1991/1992 Zeleznik was at the bottom of the table, more likely to drop out than qualify for a higher rank. Before the second part of the competition started, Jusa Bulic (father of current president Dragan Bulic) took over the management of the club with his friend Petar Vijacic in the break between the autumn and spring season with the intention to have the club achieve better results. The ascension of FC Zeleznik begins in 1992, since in six years the club made its way from the lowest rank to the First National League.