In 1965, Dorothy Sampson became a partner in the law firm Sampson and Sampson. She was the first African American female attorney in Sumter. Her area of interest was civil rights litigation, voter education and registration. Her brother, Donald J. Sampson, was he first black lawyer in Greenville.
She was a plaintiff in a suit against the South Carolina court system for full and equal employment for Blacks. She won the case on its "merits" which means both parties agreed the suit was valid and accepted the requested terms.
In 1968 Dorothy Sampson ran for Senate Seat No. 1 from Sumter and Clarendon County.