- She is a prolific composer, who composes many of the group's contemporary songs, and has been commissioned to create music for dance, choral, film, and stage productions.
- She conducts music workshops around the United States, Canada and Australia, including a workshop she created called "Building a Vocal Community: Singing in the African American Tradition".
- In 1977, she founded the Jubilee Singers, a choir at All Souls Church, Unitarian in Washington, DC.
- Barnwell earned bachelor's and master's degrees (1967 and 1968) in speech pathology from State University of New York at Geneseo, and a Ph.D. (1975) in cranio-facial studies from the University of Pittsburgh. In 1981, she also earned a post-doctoral MSPH degree, in Public Health from Howard University.
- Barnwell produced Sweet Honey in the Rock's 1998 25th anniversary album, ...Twenty-Five..., and edited Continuum: The First Songbook of Sweet Honey in the Rock.
- Barnwell's acting credits include a principal role on a television series called "A Man Called Hawk" and also appeared in the 1998 film Beloved, which starred Oprah Winfrey and Danny Glover.
- Barnwell released a solo musical album, Um Humm, in 2000.
- Barnwell has also written a children's book with CD, No Mirrors In My Nana's House. A second children's book and CD set was released in March, 2008: We Are One.
- Barnwell was named after the great Belgian violinist, Eugène Ysaÿe.
