In 1959, when LIFE magazine profiled the star of a new production of A Raisin in the Sun, Sidney Poitier was 32 and “already accepted almost without question as the best Negro actor in the history of the American theater.” In the months leading up to that assessment, he had played Porgy in Porgy and Bess and become the first black actor nominated for a Best Actor Oscar, for his work in The Defiant Ones.