[1] In 1900, Duesterberg was assigned to the East Asian Expedition Corps that saw action in China during the Boxer Rebellion, where he was lightly wounded in the right arm.

After various disagreements with the party leadership, however, Duesterberg left the DNVP in 1923 and joined the nationalistic and pro-monarchy Der Stahlhelm, which largely consisted of ex-servicemen disgruntled with the Weimar Republic.

Together with General Georg Ludwig Rudolf Maercker, Duesterberg was one of the leaders of the extreme anti-Semitic faction within Der Stahlhelm who wanted to ban Jews from joining, and expel all of the current Jewish members.

In 1931, Duesterberg played a key role in forcing the referendum on early elections in Prussia, believing this would help polarize German politics by incorporating the moderate right into the "national" camp.

[12] In October 1931, Duesterberg allied Der Stahlhelmm with the Nazis, DNVP, and other right wing groups in order to form the Harzburger Front.

The Harzburger Front attempted to bring about the downfall of Heinrich Brüning and the Weimar Republic, but it eventually dissolved due to Adolf Hitler's unwillingness to subordinate the Nazi Party to such a vast right wing coalition on a long-term basis.

After the dissolution of the Harzburger Front, Duesterberg continued to lead Der Stahlhelm and maintained the organization's alliance with the DNVP.

[15] During the 1932 presidential elections, the Nazis went out of their way to taunt Duesterberg for having Jewish ancestry with Joseph Goebbels and Richard Walther Darré being especially vicious in their attacks.

Franz Seldte, however, did enter Hitler's cabinet,[15] which undermined Der Stahlhelm and Duesterberg's authority over the organization, and thus he resigned his leadership position in 1933.