Robert James Walker was an American lawyer, economist and politician. An active member of the Democratic Party, he served as a member of the U.S. Senate from Mississippi from 1835 until 1845, as Secretary of the Treasury from 1845 to 1849 during the administration of President James K. Polk, and briefly as Territorial Governor of Kansas in 1857. He was responsible for drafting the 1849 bill that eventually established the United States Department of the Interior.

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.