Between 1971 and 1976 she served as a history professor in the African-American faculty of George Washington University and became the first full-time black member.

She also served as a primary consultant for the Schlesinger Library's Black Women Oral History Project during the course of her professional career.

[1][2][5] While she continued her education, she briefly served as a teacher in the Macon County, Alabama, segregated school system, where she taught 3rd and 4th grade in 1935 and 1936.

[2][5] On her return from Haiti, Brown moved to Alabama in 1937 and worked at the Tuskegee Institute as a history teacher until 1940.

She returned briefly in 1945 to Ohio State University to take additional classes in Eastern history and geography.

In addition to teaching and researching for her doctorate dissertation, Brown and her husband trained the earliest group of volunteers for the Peace Corps in preparation for a 1961 deployment in Ghana.

[1] In 1972, Brown travelled again, this time to African cities which include Gao, Cairo, Segou, Marrakesh, Timbuktu, Fez, Ibandan, Benin, Axum, Kumasi and Luxor.

[2][5] After a career of more than four decades,[1][8] Brown died at home aged 60 on August 3, 1976, in Washington, D.C. after battling cancer.

[1][2][5] Professor of philosophy at George Washington University Roderick S. French said at the memorial service held at National Cathedral's Bethlehem Chapel on August 7, 1976, that:[2][18] Strong, intelligent, good-humored Letitia Woods Brown was instructor to all of us.

I cannot imagine the person- man or woman- fortunate enough to be associated with her, who would have been so complacent or so dogmatic as never to have been surprised into new understanding by Letitia.

Her creative intelligence was continuous, immediate, ultimate by specialization and individual.Following her death in 1976, the Association of Black Women Historians, under Nell Irvin Painter's presidency, established an award in her name, the Letitia Woods Brown Memorial Book Award in 1983 to honor scholars whose publications in the field of African-American Women's history are the best examples.

The Letitia Woods Brown Fellowship was also established by George Washington University in the field of African American history and culture.

[6][20] During the lecture Knapp described Brown as "the first full-time African American professor at George Washington, a scholar of the history of the District of Columbia and a tireless advocate for the preservation of the city's heritage".