Johnson is a historian of Atlantic slavery and the Atlantic African diaspora.

As a historian and Black Studies scholar, Johnson researches black diasporic freedom struggles from slavery to emancipation.

She is the recipient of research fellowships and awards from the Hutchins Center for African and African American Studies at Harvard University, the Mellon-African American Digital Humanities Initiative (AADHum) at the University of Maryland, the Woodrow Wilson Foundation, the Gilder-Lehrman Institute, the Mellon Postdoctoral Fellowship Program in the Program in African American History at the Library Company of Philadelphia and the Richards Civil War Era Center and Africana Research Center at the Pennsylvania State University, and Bowdoin College (through the Consortium for Faculty Diversity).

She is the author of Wicked Flesh: Black Women, Intimacy, and Freedom in the Atlantic World (University of Pennsylvania Press, August 2020). Johnson’s Wicked Flesh: Black Women, Intimacy, and Freedom in the Atlantic World is the:

• winner of the 2021 Frank L. and Harriet C. Owsley Award for Best Book in Southern History from the Southern Historical Association
• winner of the 2021 Rosalyn Terborg-Penn Prize for Outstanding Original Scholarship on Gender and Sexuality in the African Diaspora from the Association for the Study of the Worldwide African Diaspora
• winner of the 2021 Wesley-Logan Best Book in African Diaspora History Prize from the Association of American Historians
• winner of the 2021 Lora Romero First Book Publication Prize of the American Studies Association
• winner of the 2020 Kemper and Leila Williams Prize for Louisiana History
• winner of the 2020 Berkshire Conference of Women Historians Book Prize for Best First Book dealing substantially with the topic of women, gender and/or sexuality
• winner of the 2020 Rebel Women Lit Caribbean Readers' Award
• finalist for the 2021 Frederick Douglass Book Prize from the Gilder-Lehrman Institute for the Study of American History
• honorable mention for the 2021 Barbara Christian Literary Prize from the Caribbean Studies Association
• honorable mention for the 2021 Mary Alice and Philip Boucher Book Prize from the French Colonial History Society/Société d'histoire coloniale française
• honorable mention for the 2021 Frederick Jackson Turner Prize from the Organization of American Historians
• honorable mention for the 2021 Pauli Murray Book Prize from the African American Intellectual History Society
• named a "Best Black History Book" of 2020 by Black Perspectives, the publication of the African American Intellectual History Society

She is co-editor with Lauren Tilton and David Mimno of Debates in the Digital Humanities: Computational Humanities (2024). She is guest editor of Slavery in the Machine, a special issue of archipelagos journal (formerly sx:archipelagos) (2019) and co-editor with Dr. Mark Anthony Neal (Duke University) of Black Code: A Special Issue of the Black Scholar (2017).

Her work has appeared in Slavery & Abolition, The Black Scholar, Meridians: Feminism, Race and Transnationalism, American Quarterly, Social Text, The Journal of African American History, the William & Mary Quarterly, Debates in the Digital Humanities (2nd edition), Forum Journal, Bitch Magazine, Black Perspectives (AAIHS), Somatosphere and Post-Colonial Digital Humanities (DHPoco) and her book chapters have appeared in multiple edited collections.

She is the Founding Curator of #ADPhDBooks (formerly African Diaspora, Ph.D.) which brings social justice and histories of slavery together. She is also Co-Kin Curator at Taller Electric Marronage. She is also a Digital Alchemist at the Center for Solutions to Online Violence and a co-organizer of the Queering Slavery Working Group with Dr. Vanessa Holden (University of Kentucky). Her past collaborations include organizing with the LatiNegrxs Project.

Laboratories and Workshops

As Founding Director of LifexCode: Digital Humanities Against Enclosure (LxC) lifexcode.org, Johnson leads over one hundred labs, projects, members and community partners in exploring ways digital and social media, technology and knowledges can support radical (antiracist and deconial) movement-making, intellectual production and community formation. Labs, projects and LxC members advance radical, Black feminist, digital humanities research through public facing projects that bring history, social justice, and digital media into conversation with each other. Current projects explore digital history and historical repositories related to marronage and fugitivity, Black Louisiana, Black churches in Baltimore, Black data and AI, Black Puerto Rican data and resistance, Black cultural workers, and more.

LxC is the winner of the 2020 Garfinkel Prize from the American Studies Association.

In 2024, 100% of LifexCode current and former graduate student members on the job market secured tenure-track jobs and/or postdoctoral fellowships.

Johnson is a PI on Black Beyond Data, a Black Studies computational humanities lab initiative with Kim Gallon (Black Press Research Collective) and Alexandre White (Risk and Racism Project). She is co-PI on the Diaspora Solidarities Lab (dslprojects.org) a virtual Black feminist pedagogies and practice lab. She is co-convener of the Black World Seminar with Drs. Nathan Connolly, Didier Gondola, Larry Jackson, Martha Jones, Minkah Makalani, Leah Wright Rigeur and Sasha Turner as well as convener of the Sex and Slavery Lab (2018-2019). She is affiliate faculty in the Department of the History of Medicine and a Board Member in the Program for Museums and Society.

Johnson is on IG as: @jmjafrx_ and tweets (on occasion, post-X) as @jmjafrx.