In 1919 Weber joined Freikorps Epp, commanded by Franz Ritter von Epp, and containing personalities such as Ernst Röhm, Rudolf Hess and the later "Hero of Narvik" Eduard Dietl. In the same year he was accepted into the Reichswehr and stationed in Ingolstadt and Nuremberg. Friedrich Weber married in 1924, and had four sons. In 1926 he came to Amberg for the training battalion of the 20th (Bavarian) Infantry Regiment ("20. (Bayerischen) Infanterie-Regiment"), where he was promoted to Hauptmann (captain) on April 1, 1928. In 1930 he became company commander of the "13. Minenwerfer-Kompanie" in Regensburg, and in 1935 commander of the 3rd battalion of the 20th Infantry Regiment ("Infanterie-Regiment 20") in Deggendorf.