She went on to be a professor of voice at the University of Michigan School of Music, Theatre & Dance for over 30 years before her retirement in 2015.
[3] She coached and was taught by many greats, including Felix Popper, Licia Albanese, Otto Guth and most notably, wagnerian soprano Margaret Harshaw.
[5] After making her debut with the New York City Opera, Sheil performed 15 roles with the company over the course of six years, most notably in the world premiere of Dominick Argento Miss Havisham's Fire (1979).
Sheil made her European debut at the Luzerner Theater in Switzerland where she sang for several seasons, as well as at the Heidelberger Schlossfestspiele.
[7][8] Sheil has also performed in Atlanta, Detroit, Cleveland, Los Angeles, Seattle, Hawaii, and the Kennedy Center, She is the recipient of many awards as both a singer and teacher, including the American Wagner Association Prize, the Minna-Kaufmann Ruud Competition and the 2014 Harold Haugh Award.