Mary Kaestner was born in Iowa to German emigrant Adolf August Kästner, a butcher from Crimmitschau, Kingdom of Saxony, and Laura Bell Dodge from Indiana.

[5][6] Kaestner was singing in Vienna when World War I began, and she returned to the United States.

[7] She toured North America with the San Carlo Opera Company for three seasons,[8] from 1914[9] to 1917,[4] singing leading roles in Aïda,[10] Cavalleria rusticana,[11] Lohengrin, Pagliacci, Tosca, Faust, Il trovatore,[12] and La Gioconda.

[13][14][15] "Mary Kaestner is one of those artists who has proved at each appearance that certainty and poise are her assets," commented a reviewer in 1917.

"[16] In 1919, Mary Kaestner married Italian opera conductor Carlo Peroni,[17] and retired from her stage career, saying "one famous person in a family is enough.