Chuck Hagel took the oath of office to serve as the 24th defense secretary at the Pentagon, Feb. 27, 2013, becoming the first enlisted combat veteran to lead the Defense Department. Hagel served in the U.S. Senate, representing Nebraska from 1996 to 2009. Following his Senate career, Hagel served as co-chairman of President Barack Obama's Intelligence Advisory Board and as a member of the department's Defense Policy Board. Biography