In February 1875, after the retirement of Duane Doty, Sill was elected by the Detroit Board of Education to be the superintendent of Detroit Public Schools. On July 28, 1881, the Detroit Board of Education approved Sill's plan to establish a normal school in Detroit, something that his predecessor had pushed unsuccessfully for throughout his tenure. That September, the Detroit Normal Training School for Teachers began offering classes at the city's only high school (located in the state's original capitol building). The school later became part of what is today Wayne State University.
