Simkins worked for social reform all her life, during a time when it was not only difficult for her to be of color but also a woman. Heavily involved with the NAACP and other activist groups, Simkins' most significant work involved Reverend J. A. DeLane on the 1950 South Carolina Federal District Court case Briggs v. Elliott, a lawsuit that called for equalization of black Clarendon County Schools with white schools. This case was eventually reworked as one of several cases that directly challenged the "separate but equal" doctrine in the Supreme Court case Brown v. Board of Education of Topeka in 1954. In 1981, a coalition of civil rights groups including the Columbia NAACP, the American Civil Liberties Union, ACLU, the National Council of Negro Women, and the Urban League, honored Simkins for her untiring efforts to aid the underrepresented and underprivileged. Later, she received the state's highest honor from the governor, the Order of the Palmetto, for her lifetime of work.