Johnson holds a Ph.D. and M.A. in History from the University of Maryland, College Park and a B.A. in African & African American Studies from Washington University in St. Louis where she was also a Mellon-Mays Undergraduate Fellow. Her research interests include women, gender, and sexuality in the African diaspora; histories of slavery and the slave trade; and digital history and new media and has appeared in Slavery & Abolition and Meridians: Feminism, Race and Transnationalism. As a digital humanist, Johnson is interested in ways digital and social media disseminate and create historical narratives, in particular, comparative histories of slavery and people of African descent, and the power of radical media to create social change. In 2008, she founded African Diaspora, Ph.D., a blog highlighting scholars and scholarship in the field of Atlantic African diaspora history.