Thelma Dewitty was the first black teacher to be hired by the Seattle Public School System. Dewitty was born in Beaumont, Texas. She began her career as a schoolteacher in Corpus Christi, Texas in 1933. She received her bachelor’s degree in from Wiley College in Marshall, Texas, in 1941 and transferred to teach in her native Beaumont in 1942

By the summer of 1947, she was attending graduate school at the University of Washington and also writing a mathematics book for children. Her first teaching job in Seattle was at the Frank B. Cooper School.

Dewitty’s hiring broke ground not only because of her race but because she was a married woman. During World War II, the Seattle School Board had relaxed a prior rule against married women teachers. The rule was finally eliminated in 1947, the year Dewitty was hired.

Dewitty also served on the Washington State Board Against Discrimination (WSBAD) and on the Board of Theater Supervisors for Seattle.
She joined the faculty in September 1947, after intervention on her behalf by the Seattle Urban League, NAACP, the Civic Unity Committee, and Christian Friends for Racial Equality. Thelma Dewitty died in 1977.

sources:

http://chalkboardchampions.org/education/the-amazing-thelma-dewitty-first-african-american-teacher-in-seattle-schools/