WATCH LIVE: Biden publicly swears in Kerry as secretary of State

Kerry was officially sworn in as the 68th secretary of State at a private ceremony on Friday by Supreme Court Justice Elena Kagan. 

The incoming secretary sailed through his Senate confirmation last week and began his tenure at the State Department on Monday, taking over from former Secretary of State Hillary Clinton.

Kerry joked that he had “big heels” to fill as he reached out to Clinton's former team in public remarks at State Department headquarters in Washington earlier this week.

He also defended Clinton's handling of the Sept. 11, 2012, attack in Benghazi, Libya, as the department has come under intense criticism from Republicans on Capitol Hill.

"We have tough decisions to make, but I guarantee you that I will do everything I can to live up to the high standards that Secretary Clinton and her team put in place," he added.