Rosa Valetti was born the daughter of industrialist Felix Vallentin, and was the sister of Hermann Vallentin. She first appeared on the Berlin stage and later also in Paris, Bruxelles and Vienna. During the first WW she worked for Ludwig Roth, her first husband, at the Residenz-Theater in Berlin. She also worked as a director and acted in most theaters. A meeting with Kurt Tucholsky gave her an opportunity to work in cabaret, firstly in "Schall und Rauch". In 1920 she created her own cabaret "Café Grössenwahn", in 1922 "Die Rampe" and 1923 "Comedia Valetti", in which she also worked with her brother. She played in many cabarets around Europe and appeared in the Premiere of "Die Dreigroschenoper" ("The Three Penny Opera"). In all she played in more than 40 films including in 1930 "Der Blaue Engel" ("The Blue Angel", "L'ange bleu") with Marlene Dietrich. In 1933 she left Nazi Germany for Vienna, Austria, and worked until 1935 at the Theater at der Josefstadt, making guest appearances in Prague, Czechoslovakia. In 1934 she moved to Berlin and in 1936 to Palästina. Her daughter, the actress Liesel Valetti emigrated to the USA.