Prior to her WAU appointment, Marshall served as professor of the Department of Biology at Montgomery College Takoma Park/Silver Spring Campus. She has also taught at Oakwood University in Huntsville, Alabama.
Marshall received her Ph.D.in Education from Morgan State University in Baltimore, Maryland. Her research interests include: attitudes toward science and achievement in science, informal science education and achievement in science among African American students. She has researched, published and lectured extensively on education, science and human anatomy and is the author of works such as "The Assessment of Virtual Reality for Human Anatomy Instruction" (1994) and the "Handbook of College Science Teaching" (2008).