Günther was born in Warnsdorf, Bohemia (now the Czech Republic). Her debut was in 1897 in Hermannstadt, now Sibiu, in Romania. She achieved stardom in Vienna in 1901 as O Mimosa San in The Geisha. She subsequently sang in England, France and Russia.
She created the title roles of Franz Lehár's The Merry Widow in 1905 and Leo Fall's Die Dollarprinzessin (1907), also appearing in the premieres of Fall's Die fidele Bauer (1908) and Emmerich Kálmán's Der kleine König (1912). She died in Vienna, Austria, and is buried on the Zentralfriedhof.
- Steane, J. B. (1992), "Günther, Mizzi" in The New Grove Dictionary of Opera, ed. Stanley Sadie (London) ISBN 0-333-73432-7