Rex Tillerson was sworn in as secretary of state by Vice President Mike Pence in a ceremony presided over by President Donald Trump at the White House on Wednesday evening.
Before Tillerson was sworn in, Mr. Trump spoke briefly in the Oval Office.
In a tweet, Mr. Trump congratulated Tillerson and said he is very excited for him, his family and the country.
Earlier on Wednesday, the Senate confirmed Tillerson to serve as the Trump administration’s secretary of state, making him the sixth Cabinet nominee to be approved on Capitol Hill.
John McCain of Arizona and Lindsey Graham of South Carolina in backing Tillerson to serve as the nation’s next top diplomat.
Last month, Tillerson testified at his Senate confirmation hearing about his possible conflicts involving ExxonMobil, his position regarding U.S. sanctions against Russia and his views on climate change.
Tillerson, 64, acknowledged that he would become the nation’s chief diplomat at a “Pivotal time” and listed a number of “Considerable threats” that the U.S. faces, including Russia.