Many, but not all, of the teachers in the Freedmen's Schools were single women from the North. The local African American teachers, including some who taught in secret during slavery and continued teaching during Reconstruction, aren't as well known but they were numerous and important. The schools offered a mixture of academic subjects and also a focus on vocational skills. The teachers had to be social workers as well, often tending to the basic needs of their students. They had too many students and not enough resources, but they saw the work as a calling. W.E.B. Dubois called them "women who dared."
Charlotte Forten was the first African Amreican Freedmen's teacher from the North. She published "Life on the Sea Islands" in the _Atlantic Monthly_ in 1864. She was born and raised as a free citizen.
The Freedmen's Bureau ended its support for the schools in 1870. By then, public school systems had been established in many Confederate states in part due to the activism and advocacy of black people in voting and legislation. Thus, segregated systems of education were available, until deemed unequal by Brown V Board of Education. As we all know and see where we live, especially in the public schools, de facto segregation continues to exist, as race and social class intermingle and the quality of the neighborhood school continues to depend on the wealth of the neighborhood.
My sources were the American Antiquarian Society Website (provided in the prompt) and the National Parks Service page on African American education during Reconstruction: