Age: 67
Occupation: Secretary of Defense
Previous TIME 100 appearances: 1
A career spy at the CIA, Gates was running Texas A&M University in 2006 when President George W. Bush tapped him to replace the irascible Don Rumsfeld when the Iraq war looked to be lost. Gates spent two years getting it back on track and winding it down, and he has now turned his attention to Afghanistan — where, with President Obama's backing, he has given it the attention and resources it had long lacked — and Libya. He says he's leaving his Pentagon post later this year, after killing or curbing several high-profile weapons systems like the Air Force's F-22 fighter and trying, with some degree of success, to streamline the U.S. military for the 21st century.