He was prominent in many of the struggles for civil rights. His threat of a march on Washington in 1941 contributed to the end of race restrictions on employment in the defence industries and his activities in 1948 helped to persuade President Truman to end segregation in the armed forces. In 1957, as leader of the Brotherhood of Sleeping-Car Porters, he became a vice-president of the American Federation of Labor. In 1963 he helped to organize the march on Washington for Jobs and Freedom, one of the largest civil rights demonstrations ever held in the USA.