She and her brother, Frank, grew up on the college campuses across Georgia, Alabama, Pennsylvania, and South Carolina where her parents worked.
"[1][2] She had been chosen by local advocates to integrate the school because she seemed like the kind of "nice Negro girl" whom Westover would be hard-pressed to reject.
[1][7][8][9] During her junior year at Wellesley, she married the civil rights lawyer Russell Sugarmon, and they moved to his hometown of Memphis, Tennessee, after she graduated in 1956.
[2][4][5] In 1966, she was hired to teach Spanish at Memphis State University, where she had been denied admission less than a decade earlier, becoming the school's first Black faculty member.
[7][8] An active participant in civil rights organizing, she served as chair of the Memphis NAACP's Education Committee in the 1960s, leading a boycott of local public schools.
[1][7][9] She was arrested multiple times for participating in civil rights protests, she and her children were maced, and she received threatening anonymous calls to her home.
[1][5] At Howard, she was elected chair of the Department of Romance Languages in 1974, and she established the university's doctoral programs in French and Spanish.
[1] In 1988, a year after her husband's death, DeCosta-Willis left Memphis for an appointment as commonwealth professor of Spanish at George Mason University in the Washington, D.C., area.
[1][4][7] As an academic, DeCosta-Willis was particularly engaged in African, Caribbean, African-American, Afro-Latino, and Latin American literature and culture, traveling across the Americas and to Ghana and Spain for research, and serving as associate editor of SAGE: A Scholarly Journal of Black Women and on the editorial board of the Afro-Hispanic Review.