The football department of “Turnerbund Ulm” became independent in 1926 as Ulmer Rasensportverein and in 1939 would merge with Ulmer Fußballverein, and their old clubmates in TB Ulm and TV Ulm, to form TSG Ulm 1846. Throughout this time the club played in local competition before joining the Gauliga Württemberg, one of sixteen top flight divisions formed in the 1933 reorganisation of German football under the Third Reich, for the 1939–40 season. The club played there until the end of World War II. After the war they began play in the 2nd Oberliga Süd (II) and did well enough to make occasional advances to the Oberliga Süd (I) for short stays before falling back again. In 1963, with the formation of the Bundesliga, Germany's new top-flight professional league, TSG Ulm 1846 found itself in the Regionalliga Süd (II) for a couple of seasons before slipping to tier III and IV level play. In 1968 RSVgg Ulm became part of TSG Ulm 1846.
1. Spiel- und Sportverein Ulm was formed in 1928 and, after two seasons in the Bezirksliga Bayern, joined the Gauliga Württemberg in 1933, well before their future partner, where they earned just mid-table finishes. After the war and leading up to their union with TSG 1846, they played as a third or fourth division side. Finally, in 1970, 1. SSV Ulm merged with TSG 1846 to form SSV Ulm 1846.
Logos of predecessor sides TSG Ulm 1846, 1. SSV Ulm and Ulmer FV
At the time of the merger both clubs were playing football in the tier III Amateurliga Württemberg and would continue to do so for a nearly a decade. In 1980, the combined side advanced to the 2nd Bundesliga Süd and would spend six of the next ten years playing at that level where, except for a fifth place finish in 1982, their results were well down the table. After another decade in the level III Amateur Oberliga Baden-Württemberg and Regionalliga Süd1846 would make an unexpected breakthrough after just one season in the 2nd Bundesliga with a third place finish that led to the club's promotion to the top-flight Bundesliga for the 1999–2000 season. Even though the issue was not decided until the last day of the season, Ulm could do no better than a sixteenth place finish and was returned to the second division. The 2000–01 season was an unqualified disaster for the club: they could manage only another sixteenth place finish and were sent back down to the Regionalliga Süd (III). They were then denied a license over the chaotic state of their finances which plunged the club all the way down to the fifth tier Verbandsliga Württemberg. Ulm have since worked their way back, to the Oberliga Baden-Württemberg (IV) in 2002, and the Regionalliga in 2008.
With the introduction of the Regionalligas in 1994 and the 3. Liga in 2008 as the new third tier, below the 2. Bundesliga, all leagues below dropped one tier. In 2012, the number of Regionalligas was increased from three to five with all Regionalliga Süd clubs except the Bavarian ones entering the new Regionalliga Südwest.