Born in 1831, Sarah was the oldest of eleven children raised on a farm in Queens, NY. Her younger sister, Susan McKinney Steward, became the first black woman in New York state to earn a medical degree.
Sarah moved to Brooklyn as a teenager to train as a teacher and spent eighteen years working in free schools organized by New York’s black community. In 1863, Sarah was offered the position of principal at a local public school and became the first black principal of a public school in New York City. She served as principal until her retirement in 1900.
Sarah was also active in the fight for women’s suffrage. She founded the Equal Suffrage Club in the late 1880s, leading a small group of politically minded black women in Brooklyn. Sarah was also superintendent of the Suffrage Department of the National Association of Colored Women. Sarah remained politically active to the very end of her life, dying just months after she traveled to London for the Universal Races Conference.