My colleague John Steele Gordon is correct to say that “Chief Justice of the United States” is the official title currently in use, but several points should be noted:
(1) As a lowercase, descriptive title, “chief justice of the Supreme Court” is entirely unassailable. In journalistic usage we often see it contracted still further to “Supreme Court Chief Justice,” which isn’t wrong either, just informal.
(2) Insisting on the use of official titles in all cases can lead to madness. I don’t think any harm is done by talking of “Princess Diana” instead of “Diana, Princess of Wales,” which was her official title, or by lopping off the last three words from “State of Rhode Island and Providence Plantations,” or by speaking of the intersection of “Sixth Avenue and 14th Street” rather than “Avenue of the Americas and West 14th Street.”
(3) The official designation has gone back and forth through the years. As Charles Warren wrote in The Supreme Court in United States History (1926): “The official title of the Chief Justice seems to have varied at different periods of the Court’s history. Jay was commissioned under the title of ‘Chief Justice of the Supreme Court of the United States,’ as were Rutledge, Ellsworth, Marshall, Taney, Chase, and Waite. Fuller was commissioned as ‘Chief Justice of the United States.’“ This was in 1888, a century after the Constitution was adopted.
After citing the same section of the Constitution that Mr. Gordon does, Warren continues: “The Judiciary Act of Sept. 24, 1789, provided that the Supreme Court ‘shall consist of a chief justice and five associate justices.’ The Act of July 13, 1866, c. 210, for the first time officially used the term ‘Chief Justice of the United States’ providing that ‘thereafter the Supreme Court shall consist of a Chief Justice of the United States and six associate justices.’” It’s interesting that this change took place just after the Civil War; that was also when Americans started saying “the United States is” instead of “the United States are.”
Warren goes on to cite statutes from 1869 and 1911 that refer to “Chief Justice of the United States,” and ones from 1873, 1902, and 1911 that refer to “the Chief Justice of the Supreme Court of the United States.” In fact, the two 1911 statutes with contrary wording were enacted on the same day (can you guess which day? that’s right, March 3). So while the title currently in use by the U.S. government is “Chief Justice of the United States,” the usage has been anything but consistent over the years.