The main NAACP lawyer who fought for the separate but equal case was Thurgood Marshall.
Marshall was one of the main lawyers that represented Oliver Brown in the Brown vs. Board of Education case. Oliver Brown was a parent who was challenging the "separate but equal" policy that called for segregated schools in the state of Kansas. Marshall and his team developed a strong case and got the Supreme Court to rule in favor of Oliver Brown by a vote of 9-0. This got rid of segregated schools for blacks and whites.