Vice President Joe Biden swore in now-retired Gen. David Petraeus as director of the CIA in a private ceremony on Tuesday, officially marking the four-star general's transition into a career with a far lower profile than his battlefield commands in Iraq and Afghanistan.

Petraeus, whose latest post was commander of the U.S.-led coalition in Afghanistan, retired from the Army last week after a 37-year military career. He was also one of the architects of the 2007 "surge" in Iraq.