Born Dorothea Gerson into a Jewish family in Berlin, Gerson began her career as a touring singer and actress in the Holtorf Tournee Truppe alongside actors Mathias Wieman and Ruth Hellberg in Germany, where she met and married her first husband, film director Veit Harlan.

By 1933, when the Nazi Party came to power in Germany, the German-Jewish population was systematically stripped of rights, and Gerson's career slowed dramatically.

She also began recording in the Yiddish language during this time, and the 1936 song "Der Rebe Hot Geheysn Freylekh Zayn" became highly regarded by the Jews of Europe in the 1930s.

Gerson's most memorable recordings from this era were the German-language songs "Backbord und Steuerbord", and "Vorbei" (Beyond Recall), which was an emotional ballad memorializing pre-Nazi Germany: They're gone beyond recallA final glance, a last kissAnd then it's all overunder the frame of eternityA final word, a last farewellIn 1936, Gerson relocated with relatives to the Netherlands, fleeing Nazi persecution.

In 1942, Gerson and her family were seized trying to flee to Switzerland, a neutral nation in World War II Europe.