Simplify the following text for a Grade 8 native English-speaking person.
Original: Donald Henry Rumsfeld ( born July 9 , 1932 ) is an American 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 .
Simplified: Donald Henry Rumsfeld ( born 9 July 1932 ) is a United States businessman and politician . Rumsfeld was the 13th United States Secretary of Defense under President Gerald Ford from 1975 to 1977 , and the 21st Secretary of Defense under President George W. Bush from 2001 to 2006 .