Von Arendt worked as a stagedesigner. He joined the SS in 1931 and the Nazi Party in 1932. The same year, he helped start the "Bund nationalsozialistischer Bühnen- und Filmkünstler" ("Union of national-socialist stage and movie artists"). After Adolf Hitler began to rule Germany in 1933, the name was changed to "Kameradschaft deutscher Künstler" ("fellowship of German artists").
Von Arent was made "Reichsbühnenbildner" ("Reich stage designer") in 1936 and "Reichsbeauftragter für die Mode" ("Reichagent for fashion") in 1939. In 1944, he was given the rank of SS-Oberführer (senior colonel).