A member of the liberal Deutsche Demokratische Partei, Weiss was known as a key player in the political tensions during the Weimar Republic and a staunch defender of parliamentary democracy against extremists on the left and right.
Active in the Jewish community of Berlin, Weiss was a board member of the (reform) rabbinical seminary and a member of the Centralverein deutscher Staatsbürger jüdischen Glaubens (Central Union of German Citizens of Jewish Belief), the organization dedicated to protecting the civil and social rights of Jews in Germany while at the same time cultivating their German identity.
Walther Rathenau, the Jewish industrialist and politician who served Weimar governments in several capacities including that of Foreign Minister was assassinated in 1922, two months after the signing of the Treaty of Rapallo.
In 1927 Weiss ordered the shutting down of the Berlin branch of the Nazi party and in the same year had 500 of their members arrested for belonging to an illegal organization when they returned from a rally in Nuremberg.
On 12 May 1932, he led a group of police to restore order in the Reichstag building on the request of its president, Paul Löbe, after Nazi deputies assaulted journalist Helmuth Klotz [de] there during the Röhm scandal.
[1] While in office, Weiss was the target of a constant campaign of vilification organized by Joseph Goebbels, then a prominent Nazi activist, later the Reich Minister of Propaganda.
Franz von Papen, Chancellor of Germany in 1932 and Vice-Chancellor when Adolf Hitler came to power, had both Weiss and his superior arrested, albeit for one day only.
Weiss's police force was ordered to arrest their former Deputy Chief and Hermann Göring offered to pay a reward for anyone who assisted in his capture.
"He was a man of extremes, a Jew imbibing Prussian values, small in stature, large in responsible behaviour and a staunch democrat," wrote Uwe Dannenbaum in an article in the German newspaper Die Welt to mark the naming of the forecourt of the Friedrichstrasse railway station in Berlin in honour of the former police chief.
In his A Quiet Flame (2008) Kerr has Weiss taking refuge in the Chinese embassy at the time of the Reichstag fire, and then removed by Gunther to the sanctuary of the Hotel Adlon.