Age: 63
Occupation: Chairman of the Joint Chiefs of Staff
Previous TIME 100 Appearances: 0
Nominated to succeed General Peter Pace by Defense Secretary Robert Gates in June 2007, Mullen was confirmed to a second term under President Obama in 2009. Straddling Republican and Democratic administrations hasn't seemed a problem for Mullen, who previously served as commander of U.S. naval forces in Europe, even on the most sensitive political issues. Mullen fully supported Obama's decision to repeal "Don't ask, don't tell." "It is my personal belief that allowing gays and lesbians to serve openly would be the right thing to do," he told the Senate Armed Services Committee recently.