In those movies, she was frequently cast in the comic roles of nagging wife (for example in Ungeküsst soll man nicht schlafen gehn opposite Hans Moser), evil mother-in-law, or understanding housekeeper, whether in rural (Heimatfilme) or urban settings.

She occasionally also appeared in serious films, including her cameo performance as the porter's wife in The Third Man (1949),[1] and in Embezzled Heaven [de] based on the novel by Franz Werfel in 1958.

Having finished grammar school (Gymnasium), Rosar attended the University of Music and Performing Arts and made her stage debut in the Vienna Prater under director Josef Jarno in 1910.

Rosar initially appeared in classical roles, however, in her advanced years she embodied resolute Viennese women in numerous comedies.

After the World War II, Rosar concentrated on film, radio and television work, starring in more than 100 movies during her acting career.