Harold Brown (September 19, 1927 – January 4, 2019) was an American nuclear physicist who served as United States Secretary of Defense from 1977 to 1981, under President Jimmy Carter. Previously, in the John F. Kennedy and Lyndon B. Johnson administrations, he held the posts of Director of Defense Research and Engineering (1961–1965) and United States Secretary of the Air Force (1965–1969).
A child prodigy, Brown graduated from the Bronx High School of Science at age 15, and earned a Ph.D. in physics from Columbia University at age 21.
