Born in Crescent City, Florida, in 1889, he began organising workers at the age of 22. During the First World War he founded The Messenger (later renamed The Black Worker) and campaigned for more positions in the war industry and the armed forces for African Americans.
In 1925, as founding president of the Brotherhood of Sleeping Car Porters, Randolph began organising black workers and it became the first such union to join the American Federation of Labor (AFL), which until then had barred blacksAfrican Americans from membership.
After a bitter struggle and fluctuating fortunes for several years, The Brotherhood won its first major contract with the Pullman Company in 1937. However, tensions with the AFL continued, and the following year he took his union out of the AFL over its failure to fight discrimination in its ranks, and joined the newly formed Congress of Industrial Organizations (CIO).
During the Second World War he led campaigns to improve African American employment in the federal government and in industries, and it was a threat to march on Washington in 1941 that led President Franklin D. Roosevelt to eventually issue Executive Order 8802, barring discrimination in defence industries and federal bureaus.
After the War, Randolph established the League for Nonviolent Civil Disobedience Against Military Segregation, resulting in a further Executive Order from President Harry S. Truman banning segregation in the armed forces.
When the AFL merged with the CIO in 1955, Randolph was made a vice president and member of the executive council of the combined organisation, and emerged as one of the most visible spokespeople for African-American civil rights.
In a repeat of his 1941 threat to march on Washington, Randolph became a director of the famous March on Washington for Jobs and Freedom in 1963.
In 1965, he formed the A. Philip Randolph Institute for community leaders to study the causes of poverty. He died in 1979.