The Chief Justice of the United States is the head of the judicial branch of the government of the United States, and presides over the U.S. Supreme Court. The highest judicial officer in the country, the Chief Justice leads the business of the Supreme Court and presides over the Senate during impeachment trials of the President. In modern tradition, the Chief Justice also has the duty of administering the oath of office to the President, but this is not required by the Constitution or any other law.
See more at Wikipedia.org...