Sivasspor were originally formed on May 14, 1932 in Sivas as Sivas Gençlik. They sported Kırmızı-Beyaz (Red-White) shirts and Beyaz (White) shorts. They played many matches at the amateur level in their early years before they were allowed to play professionally. By the mid-1960s, Sivas Gençlik merged with Yolspor and Kızılırmak. They had hoped that this merger would help their push to join the professional leagues, the league closed their doors to Sivasspor once more.
There were several boycotts until July 1, 1967, when Sivasspor was allowed to play professional football in Turkey. Sivasspor started out in the Second League, White Group. Due to there being many new clubs, the Turkish Football Federation decided to create a third league. They were permitted into the Second League along with Afyonspor, Balıkesirspor, Giresunspor, Kastamonuspor, Malatyaspor, Orduspor, Uşakspor, and Taksim GK. During their first professional season, Sivasspor finished 16th in their group, a mere 4 points from relegation. They also finished in the bottom half of the table the following season. They came close to promotion to First League in 1971–72 and 1972–73 seasons but finished 2nd behind Şekerspor and Adana Demirspor.
Sivas SK's classic home kit
Sivasspor would remain in the lower leagues until winning the Second League in 2005, gaining automatic promotion. The club finished 8th in their first season in the Turkcell Super League. Werner Lorant lead the team to key victories over clubs like Beşiktaş J.K. and Gençlerbirliği. At the end of their first season in the top flight, they finished with a record of ten wins, thirteen draws, and eleven losses, totaling out to 43 points. The club then finished 4th in the 2007–08 season, finishing on the same number of points as the second and third place teams but with an inferior goal difference. Sivasspor had the championship in their sights until the penultimate match, when they were beaten 5–3 by eventual champions Galatasaray. The 2008–09 season saw them finish 2nd after leading the table for much of the season. After losing their final match of the season, they finished behind leaders Beşiktaş by 5 points.
On September 17, 1967 during a match against Kayseri Erciyesspor (Then Kayserispor) played at the Kayseri Atatürk Stadium, a disaster occurred with 40 dead and at least 300 injuries among the fans, which was the worst sporting-related event in Turkey. Almost all casualties were Sivasspor fans, who perished in a stampede after chaos broke out in their ranks, due to attacking Kayserispor fans. The match was finished 1–0 in favour of the Kayseri side. After the disaster, Kayseri Erciyesspor and Sivasspor played different groups of the 2nd league until the 1990–91 season. That year, both teams reconciled and played in the Fourth Group of the Third League (now TFF Second League). Kayseri Erciyesspor were champions and promoted to Second League.