William Cotten’s reviews have described his singing as “sweet-voiced” and “honey-toned”, and his performances as “bursting full of life”, “a natural scene-stealer”, “making his part as lyrically enticing as a whole string of Schubertian Lieder.” He performed with the Boston Opera Theater Company in The Marriage of Figaro, a production which was filmed in Vienna and aired on PBS's Great Performances. He also performed in Paris, at the Gran Teatre del Liceu in Barcelona, and in the American Repertory Theater’s world premiere of Robert Moran and Phillip Glass's The Juniper Tree. He has sung throughout the Boston and New England area, and was a Fellow at the Tanglewood Music Center. He is currently on the faculties of The Boston Conservatory and the College of the Holy Cross, and has taught at the New England Conservatory. His students have sung throughout the United States and Europe in opera, concert, national tours, on Broadway, and have won numerous awards.