Donald Henry Rumsfeld was an American politician, government official and businessman who served as secretary of defense from 1975 to 1977 under president Gerald Ford, and again from 2001 to 2006 under President George W. Bush. He was both the youngest and the oldest secretary of defense. Additionally, Rumsfeld was a four-term U.S. Congressman from Illinois (1963–1969), director of the Office of Economic Opportunity (1969–1970), counselor to the president (1969–1973), the U.S. Representative to NATO (1973–1974), and the White House Chief of Staff (1974–1975). Between his terms as secretary of defense, he served as the CEO and chairman of several companies.