Age: 62
Occupation: U.S. Secretary of State
Previous TIME 100 Appearances: 5
President Obama tapped his former primary opponent to be America's top diplomat, and in 2009 she became a key member of his team, overseeing outreach to Iran, nuclear talks with Russia and a surge in advisers to Afghanistan. With her commitment to foreign aid, she is re-emphasizing the State Department's role in controlling development projects around the world and defending human rights worldwide.