The German soprano, Käthe Nentwig, completed her singing studies in Breslau and Vienna.
In 1939 Käthe Nentwig made her debut at the Stadttheater of Stadttheater von Plauen as Queen of the Night. She remained in Plauen until 1940. Engagements at the Stadttheater of Wilhelmshaven (1940-1941) and the Nationaltheater of Weimar (1941-1943) followed. In 1943 she was appointed to the Staatsoper of Munich. Here she sang Pagen Oscar in Maskenball by Verdi and Blondchen in Entführung aus dem Serail; then the picks of her coloratura repertoire were as Zerbinetta in Ariadne auf Naxos, the Queen of the Night in Zauberflöte, Gilda in Rigoletto, Despina in Così fan tutte, Sophie in Rosenkavalier and Susanna in Le Nozze di Figaro. In 1943 she sang at the Salzburg Festival a small role in Zauberflöte, and in 1953 the soprano solo in the Mozart Requiem. In 1953 she appeared at the Covent Garden Opera in London as Xanthe in Die Liebe der Danaë by R. Strauss. She remained until 1957 in engagement at the Staatsoper of Munich, and since then appeared as a constant guest at the Opera House of Cologne, where she appeared also under the name Käthe Schmitt-Nentwig.
Recordings: On Nixa she appears in the complete operas Il Re Pastore, Der Schauspieldirektor and Così fan tutte by Mozart, on DGG in Hoffmanns Erzählungen by Offenbach; also on Vox/Melodram exists a recording of R. Strauss' opera Daphne from Munich (1950).