Mr. Brown called the treaty episode his deepest regret in office. But in an interview with The New York Times, he spoke of one satisfying outcome. “I guess I’m proudest of the fact that we have remained at peace these four years,” he said. Mr. Carter awarded him the Presidential Medal of Freedom, the nation’s highest civilian honor.
Harold Brown was born in New York City on Sept. 19, 1927, the only son of Abraham Brown, a lawyer, and Gertrude Cohen Brown. From childhood he was considered a genius. At 15, he graduated from the Bronx High School of Science with a 99.52 average. At Columbia University, he studied physics and earned three degrees — a bachelor’s in only two years, graduating in 1945 with highest honors; a master’s in 1946; and a doctorate in 1949, when he was 21.
He married Colene D. McDowell in the early 1950s. She died last year.
After several years of teaching and research, Mr. Brown was recruited by the Atomic Energy Commission in 1952 to work at the Livermore laboratory, where nuclear weapons were being designed.
From 1961 to 1965, he was director of defense research and engineering, the Pentagon’s third-ranking civilian, responsible for weapons development, and one of Defense Secretary Robert S. McNamara’s “whiz kids.” He was the Air Force secretary from 1965 to 1969, and over the next eight years he was president of the California Institute of Technology in Pasadena.
After leaving the Pentagon in 1981, Mr. Brown taught at the Paul H. Nitze School of Advanced International Studies at Johns Hopkins University for several years, and from 1984 to 1992 he was chairman of the school’s foreign policy institute.
Since 1990, he had been a partner at Warburg Pincus, the New York investment firm. He served on the boards of many companies, including Altria, CBS, IBM, Mattel and Rand.
In addition to his daughter Deborah, he is survived by another daughter, Ellen Brown; a sister, Leila Brennet; and two grandchildren.