[8] Before completing her undergraduate degree, McMillan Cottom worked as an enrollment officer at a technical college, a job that would inform her later research and her first book.

[15] In 2015, McMillan Cottom was appointed assistant professor of sociology at Virginia Commonwealth University and a faculty associate at the Berkman Klein Center for Internet & Society.

[3] Before the publication of her book Lower Ed, McMillan Cottom was known primarily as an essayist and academic expert on issues of inequality, higher education, and race.

[23] In addition to her own writing, McMillan Cottom has been featured in The New York Times,[24] National Public Radio (NPR),[25] Harvard Educational Review,[26] Mother Jones,[27] Inside Higher Ed,[28] and The Daily Show.

[30][31] In 2019, McMillan Cottom and Roxane Gay launched a podcast called Hear to Slay to "amplify the voices and work of black women".

[33] McMillan Cottom's 2017 book Lower Ed analyzes the for-profit educational sector from the perspective of students trying to navigate a "risky and highly variable" economy.

These essays touch on topics including sexual abuse, divorce, and the death of a child to discuss broader issues in race, beauty, and education, such as why black women can never be seen as beautiful, why universities prefer African students to African American students, and how assumptions about wealth, competence, and pain undermine black women's efforts to achieve health and financial security.

[6] Rebecca Stoner, writing for Pacific Standard, praised the broad appeal of Thick, noting that McMillan Cottom "makes it possible for her readers, whether or not they are black women, to understand the interdependent nature of our oppressions".