In 1928 she was called to Berlin and within a short period became one of the favourite singers of conductor Otto Klemperer – first at the Kroll Opera House, later on at the prestigious Staatsoper Unter den Linden.
Musicologist Elizabeth Forbes describes her singing: "Her voice, bright-toned, light and very flexible, and her charming, diminutive appearance, invariably drew adjectives such as 'enchanting' and 'winsome' from the critics.
[6] Furthermore, in this year her first sound film was released, the light comedy Two Hearts in Waltz Time – with Eisinger as Anni Lohmeier and with the popular actor Willi Forst in a leading role.
Her singing covered a broad repertory spanning from Mozart and Auber to C. M. Weber, Albert Lortzing, Puccini, Lehár and Strauss, including works of Leo Fall, Bruno Granichstaedten, Ralph Benatzky and Robert Stolz.
Her male partners in duets were Siegfried Arno, Paul Morgan, Joseph Schmidt, Erik Wirl and Richard Fritz Wolf.
Eisinger continued to sing at Prague State Opera until 1937, but already in 1934 she was invited by German emigrants Fritz Busch and Carl Ebert to participate at the first Glyndebourne Festival.
[3] The 1935 Glyndebourne recording of Così fan tutte, conducted by Fritz Busch, gives an idea of Eisinger's voice, her stylish singing and her delightful personality.
In 1939 Eisinger sang Ilya in a university production of Mozart's Idomeneo at Cambridge and acted in Beatrice Saxon Snell's musical Georgian Springtime at the Embassy Theatre in London – with Geoffrey Dunn, Frederick Ranalow, and George Skillan in the cast.
Furthermore, she participated in the movie comedy Young Man's Fancy and was invited by BBC to sing in Die Fledermaus and in Arlecchino, a single act opera by Ferruccio Busoni.
Her last operatic performances were a series of seven performances of Così fan tutte in the original Glyndebourne production of Carl Ebert at the Edinburgh International Festival in August and September 1949 – together with a prominent cast consisting of Suzanne Danco (Fiordiligi), Sena Jurinac (Dorabella), Petre Munteanu (Ferrando), Marko Rothmüller (Guglielmo), John Brownlee (Don Alfonso) and the Royal Philharmonic Orchestra conducted by Hans Oppenheim.