While on assignment for the FEPC, Henderson was denied service in a Southern Railways dining car. He complained to the Interstate Commerce Commission and, with the backing of the NAACP, appealed his case to the U.S. Supreme Court. In 1950 the court ruled that segregated dining cars violated the Interstate Commerce Act. In addition to working for the FEPC, Henderson was the executive director of the Illinois State Commission on the Urban Colored Population (1940-1941), the executive director of the American Council on Human Rights (1948-1955) and legal council to the Committee on Government Operations of the U.S. House of Representatives (1955-1982). Henderson taught political science at Howard University and sociology at Dillard University and was an adviser to Adlai Stevenson during his 1956 presidential campaign.
