She was an extremely educated woman for the time, she studied piano, pipe organ, and voice culture at the Oberlin Conservatory of Music and in 1889. Marshall was the first African American to complete the program and earn a Mus.B. degree (Bachelor of Music degree). In 1903 she founded the Washington Conservatory of Music. According to blackpast.org "Marshall's conservatory was a landmark in the history of black education. The Centre sponsored regular concerts for the black community, trained many prominent musical professionals and attracted the nation's most talented musicians as teachers. It remained in operation until 1960." [blackpast.org; Bahá'í Chronicles]