William Sharp, usually classified as a bass-baritone, has a repertory spanning 900 years but is especially well known for his long advocacy of vocal music by American composers and for performances of Bach and other early music. He has also had a long career as an educator.

Sharp was born in Kansas City, Missouri, in 1951. As a teenager, he became interested in medieval and Renaissance music well before those repertories entered general circulation. Sharp attended Lawrence University in Wisconsin, majoring in music, and as an undergraduate, he formed an early music ensemble there. He went on to the Eastman School of Music in Rochester, where he was introduced to opera and aimed at first as a career in that field, believing that it would be impossible to make a living performing art song. He moved to New York in the 1970s with that goal in mind but soon won an audition to join the Waverly Consort early music ensemble. Since then, he has mostly performed in the fields of art song, choral music, and Renaissance and Baroque music. In 1982, he made his recital debut at New York's 92nd Street Y.

Sharp's reputation grew rapidly, and within two years, he was appearing at Lincoln Center. As a vocal recitalist, he has been strongly identified with the music of Ives and made the first recordings of the Ives songs I knew and loved a maid, I travelled among unknown men, and The Song of the Dead. Sharp has also performed music by many other American composers, and his debut recording, released on New World Records in 1989, featured music by Virgil Thomson, Paul Bowles, and Lee Hoiby; the album earned a Grammy Award nomination for Best Classical Vocal Performance. The following year, Sharp was featured on the first recording of Leonard Bernstein's final work, Arias and Barcarolles.

Sharp was a member of the American Bach Soloists and has performed Bach widely with early music groups and major American symphony orchestras. His orchestral credits include appearances with the Cincinnati Symphony (both in Cincinnati and at New York's Carnegie Hall), the Chamber Music Society of Lincoln Center, and the National Symphony in Washington in Brahms Ein deutsches Requiem, Op. 45. Sharp started teaching in 1977 and began teaching voice at Boston University in 1993 when he was in the midst of recording a complete cycle of Ives songs for the Albany label. He joined the faculty of the Peabody Conservatory in Baltimore in 2002 and remains on the faculty there. Sharp has a recording catalog of more than 60 albums; in 2021, he was heard on the Naxos album Arthur Farwell: America's Neglected Composer. ~ James Manheim, Rovi