- The United States secretary of the treasury is the head of the United States Department of the Treasury, and is the chief financial officer of the federal government of the United States. The secretary of the treasury serves as the principal advisor to the president of the United States on all matters pertaining to economic and fiscal policy. The secretary is, by custom, a member of the president’s cabinet and, by law, a member of the National Security Council, and fifth in the U.S. presidential line of succession.