Donald Henry Rumsfeld (born July 9, 1932) is an American government official, Republican politician and businessman who served as the 13th Secretary of Defense from 1975 to 1977, under President Gerald Ford, and as the 21st Secretary of Defense from 2001 to 2006, under President George W. Bush. He is both the youngest (at 43 years old) and the oldest person (at 74 years old) to have served as Secretary of Defense, as well as the only person to have served in the position for two non-consecutive terms. Combined, he is the second longest-serving defense secretary after Robert McNamara.

Rumsfeld was White House Chief of Staff during part of the Ford Administration and also served in various positions in the Nixon Administration. He was elected to four terms in the United States House of Representatives, and served as the United States Permanent Representative to NATO. He was president of G. D. Searle & Company from 1977–1985, CEO of General Instrument from 1990–1993, and chairman of Gilead Sciences from 1997-2001. Rumsfeld is one of the key people responsible for the restructuring of the military after 2001, for designing the national response to the 9-11 attacks, and for taking charge of the wars against Afghanistan (2001-present) and Irag (2003-2010), including the controversial treatment of prisoners. At first highly popular with the media for his outspokenness, he lost political support as the wars in Iraq and Afghanistan dragged on and was forced to retire immediately after the 2006 election.

Donald Henry Rumsfeld was born on July 9, 1932, in Evanston, Illinois, to George Donald Rumsfeld and Jeannette (née Huster). His great-grandfather, Johann Heinrich Rumsfeld, emigrated from Weyhe near Bremen in Northern Germany in 1876. Growing up in Winnetka, Illinois, Rumsfeld became an Eagle Scout in 1949 and is the recipient of both the Distinguished Eagle Scout Award from the Boy Scouts of America and its Silver Buffalo Award in 2006. He was a camp counselor at the Northeast Illinois Council's Camp Ma-Ka-Ja-Wan in the late 1940s and a ranger at Philmont Scout Ranch in 1949. Rumsfeld later bought a vacation house 30 miles (48 km) west of Philmont at Taos, New Mexico.