James Rodney Schlesinger was an American economist and public servant who was best known for serving as Secretary of Defense from 1973 to 1975 under Presidents Richard Nixon and Gerald Ford. Prior to becoming Secretary of Defense, he served as Chair of the Atomic Energy Commission (AEC) from 1971 to 1973, and as CIA Director for a few months in 1973. He became America's first Secretary of Energy under Jimmy Carter in 1977, serving until 1979.

The United States secretary of defense (SecDef) is the head of the United States Department of Defense, the executive department of the U.S. Armed Forces, and is a high-ranking member of the federal cabinet. The secretary of defense's position of command and authority over the military is second only to that of the president of the United States, who is the commander-in-chief. This position corresponds to what is generally known as a defense minister in many other countries. The secretary of defense is appointed by the president with the advice and consent of the Senate, and is by custom a member of the Cabinet and by law a member of the National Security Council.