In 1920, when it turned out that the Reichswehr, which was busy reconstituting itself, could no longer find a job for him, he was discharged with the rank of captain.

Already by 1919, Weiss had been busying himself as a member of the state leadership of the Bavarian Inhabitants' Defence (Einwohnerwehr), through which he was appointed editor of the magazine Heimatland (Homeland), a publication with strongly NSDAP (the Nazi Party) leanings.

However, after Hitler and the Nazi Party had come to power, Weiss organized the "equalization" of the press, though he also saw to it that individual journalists could keep their jobs despite the Editor Law (Schriftleitergesetz).

[4][5] Further important functions bestowed upon Weiss between 1933 and 1945 were leader of the Reich Association of the German Press, and in the same period Member of the Reichstag.

In 1945, after the Second World War had ended, Weiss was interned, and on 15 July 1949 a denazification court sentenced him to three years in a labour camp, confiscated 30% of his wealth, and placed a 10-year ban on his professional activities.