Mr. Mangum went on to build a career as diverse as it was accomplished. He became the youngest deputy police commissioner in New York City history, the chief of President Lyndon B. Johnson’s War on Poverty in the Northeast, and the chairman of human rights for New York State. In 1943, as a 22-year-old police officer, he helped found the Guardians Association, a fraternal group for blacks in the New York City Police Department. It still exists. In 1963, he joined with David N. Dinkins (who went on to become the first black mayor of New York), Jackie Robinson and business leaders to start One Hundred Black Men, an organization to enhance opportunities and provide role models for minorities. It, too, is still operating, with 116 chapters and more than 10,000 members in the United States and throughout the world. He was the first president of both organizations. He was also chairman of the New York affiliate of the National Urban League. In 1971, he became the first black judge appointed to the New York State Court of Claims, which adjudicates claims against the state. He earned a bachelor’s degree in the social sciences from the City College of New York in 1942. A congressman appointed him to the United States Military Academy at West Point, but Mr. Mangum turned it down to continue to help his family financially. He was accepted by the Police Department in December 1942 and assigned to walk a beat at a salary of $1,320 a year. In 1944, he was drafted into the Army and sent to the Philippines, where he was a courts-martial officer, an assignment that piqued his interest in becoming a lawyer. He was discharged as a first lieutenant. He returned to the Police Department in 1946 and coordinated Police Athletic League activities in Harlem while earning a law degree from Brooklyn Law School. He later earned a master’s in public administration from New York University. In 1966, Mr. Mangum was appointed director of the Northeast region of the Office of Economic Opportunity, the lead agency in President Johnson’s war on poverty. Gov. Nelson A. Rockefeller named Mr. Mangum chairman of the State Commission on Human Rights in 1967. In 1971, Governor Rockefeller appointed Mr. Mangum to the claims court, where in 1978 he made the nation’s first ruling on the safety of highway guard rails. He ordered the state to pay $475,000 in damages to an injured driver. He was later general counsel of Beth Israel Hospital in Manhattan. Mr. Mangum’s marriage to the former Gladys Scott ended in divorce. He is survived by his partner of 30 years, Barbara Baxter Cuyjet; his son, Paul; three stepsons; and besides Ms. Hunter-Cuyjet, three other grandchildren.