In 1933, German football was reorganized under the Third Reich into 16 top flight Gauligen and in 1939 FSC attempted to qualify for the Gauliga Baden but were beaten by VfR Achern (2–3, 5–3).

From 1942 to 1945, during World War II, the club played as part of the combined wartime side Kriegspielgemeinschaft Singen/Gottmadingen alongside SpVgg Gottmadingen and Reichsbahn SV Singen.

Following the war occupying Allied authorities ordered the dissolution of most organizations in Germany, including sports and football clubs.

In 1947, the team returned to top flight competition in the French-controlled Oberliga Südwest-Süd and in 1948 captured the South Baden Cup.

They spent the 1958–59 season in the Amateurliga Südbaden (III) and captured the German amateur football championship that year, defeating Arminia Hannover 3–2.

They finished the 1963–64 campaign in second place and lost a Regionalliga (II) promotion playoff to FV Ebingen.

In 1971 and 1972, they again took part in qualifying play for the Regionalliga Süd (II), but failed in both attempts losing to SV Waldhof 3–5 and 0–1.

The club resurfaced in the Oberliga Baden-Württemberg in 1997 for a three-season stint before again slipping into lower-tier competition.

[3] In 1974, with the reorganisation of German football, Singen, alongside two other clubs, was moved to the Amateurliga Südbaden.

On league level, it continued to play in the now tier-seven Landesliga Südbaden Staffel 3 in 2008–09, where team took out the championship and earned promotion.