She graduated from Dunbar High School, and from Wilberforce College in 1948, and earned a master's degree in education administration at Miami University in 1951.

[1][3] In 1961, she helped organize the Westwood neighborhood of Dayton against a zoning variance for a storage yard.

[5] She was active in the African Methodist Episcopal Church,[6][7] and served on the board of directors at Unity Bank.

[11][12] In 1975, Sumlin represented the sorority at International Women's Year events in Washington, D.C., and Mexico City.

[3] In 1997, Sumlin gave a presentation at the Fourth African American Summit in Harare, Zimbabwe.