Her father, Friedrich Schlemm, was a chorister at the Oper Frankfurt, and she studied in Berlin with Erna Westenberger. She made her debut at the Halle Opera House in Halle an der Saale, as Nanette in Lortzing's Der Wildschütz, in 1946. In 1949 she joined the Komische Oper Berlin, where she remained until 1961, during that period her roles included Susanna, Marenka, Donna Elvira, Desdemona, Manon Lescaut, Octavian, Arabella, etc. She also sang at the opera houses of Cologne, Hamburg, Dresden, Frankfurt, Stuttgart, Munich, and at the Bayreuth Festival, etc.
A superb singing-actress and highly versatile artist, Schlemm was equally at home in comic and dramatic roles. She was once married to conductor Wolfgang Rennert.