The league was formed at the end of the 2011-12 season, when the clubs from the Regionalliga Süd, except those from Bavaria, were joined by the clubs of the Regionalliga West from Saarland and Rhineland-Palatinate.
The German league system had been reformed in 2008, when the 3rd Liga was established and the number of regional leagues increased from two to three. A further alteration was made in 2011. This was prompted by the large number of insolvencies in the fourth tier, caused by high costs and infrastructure requirements while, at the same time, the clubs at this level complained about low incomes and lack of interest from TV broadcasters. Regionalliga stadiums had to have at least 1,000 seats and a separate stand with separate entrance for away spectators; and such requirements were seen as causing excessive financial strain on amateur clubs. Many clubs also struggled to cope with the 400-pages long license application, as they had to rely on volunteers rather than being able to draw on permanent staff.
This led to Oberliga champions sometimes even declining their right to promotion to avoid the financial risks of the Regionalliga, thus breaking a basic principle of German football, that league champions would almost always be promoted.
In October 2010, at a special conference of the German Football Association, the DFB, 223 of the 253 delegates voted for a reform of the league system at the fourth level. The number of Regionalligas was to be expanded to five, with the re-establishment of the Regionalliga Nordost, the formation of the Regionalliga Bayern and a shift of the Regionalliga Süd to the new Regionalliga Süd/Südwest, later renamed Regionalliga Südwest.
The suggestion for the league reform had come from Bavaria, where, in a meeting of the Bavarian top-level amateur clubs at Wendelstein, the financial survival of the leagues and clubs in the current system had been questioned. This meeting resulted in the publication of what was called the Wendelsteiner Anstoß, which demanded a clear demarcation between professional football on the first three tiers of German football and amateur football below that. For this purpose, the paper also demanded a reestablishment of the German amateur football championship as an incentive and goal for top amateur clubs who did not want to turn professional.
The league champions of the five new regional leagues no longer have the right to direct promotion to the 3rd Liga. Instead, the five league winners and the runners-up of the Süd/Südwest would play-off for three promotion spots. The play-offs are played in home-and-away format, and the two clubs from the Süd/Südwest region can not be paired against each other.
The new league was nominally going to have 18 clubs; however, in its first, transitional season the DFB permitted up to 22 clubs in the league. Restrictions existed on reserve sides. No more than seven reserve teams were permitted per Regionalliga; should there be more in a league the additional ones would have to be moved to a different Regionalliga. Reserve teams of 3rd Liga clubs were not permitted to play in the Regionalliga. The make up of the clubs entering the new Regionalligas from the leagues below was left to the regional football association and not regulated by the DFB.
One exception to the rule was the Bavarian club FC Bayern Alzenau, who had traditionally played in Hesse's league system. This club would participate in the new Regionalliga Südwest, at their own request, rather than in the Regionalliga Bayern.
19 clubs qualified to play in the league's first season (2012–13):
1 At the end of the 2013–14 season Eintracht Frankfurt decided to withdraw its reserve side from all competitions after a ruling by the DFL allowed all Bundesliga and 2. Bundesliga clubs to freely choose whether or not to operate an under-23 reserve team. Previous to that such teams had been compulsory.
2 SSV Ulm 1846 declared insolvent at the end of the 2013–14 season and was relegated.