Alexander Ernestinoff served as the director of the Indianapolis Maennerchor from 1880-1882 and again from 1896-1897 after Carl Barus's resignation. In 1883, as director of the Indianapolis Liederkranz, he acted as the festival conductor of the Indiana Saengerbund's Eighth Song Festival, and one year later he was elected the conductor of Lyra, another Indianapolis singing society. When the Musikverein (an organization that included an orchestra and two choruses) was formed in 1897, he was chosen to be its first director. (In the photograph of the Musikverein men's chorus at right, Ernestinoff is the fifth man from the left in the front row.) During this period, Ernestinoff also taught singing at the Normal College of the American Gymnastic Union. When the Indianapolis Orchestra was formed in 1911, he became its first director.

Photograph of Musikverein chorus, 1914 (Alexander Ernestinoff, director of the Musikverein, is the fifth man from the left in the front row.)