After having played in the tier-one Kreisliga Württemberg (1920–22) and then the Bezirksliga Württemberg-Baden (since 1926) and winning the title there in 1931, Union's most significant football achievement was their 1933 championship in the Gauliga Württemberg, one of 16 top-flight divisions formed that year in the reorganization of German football under the Third Reich.

They immediately bounced back and earned a string of upper table finishes before again being sent down for a single season in 1941–42.

After two more seasons in the Gauliga the team withdrew from competition in November 1944 as World War II overtook the country.

In 1938, Böckingen took part in the opening round of the Tschammerpokal, predecessor of today's German Cup, where they were put out by Bayern Munich (0:7).

A second place finish there in 1950 was followed by a failed promotion attempt, and a poor campaign in the subsequent season saw the club fall from the 2.