[7] The formal office of the United States postmaster general was established by act of government on September 22, 1789.

[9]: 120 After passage of the Pendleton Civil Service Reform Act in 1883 and prior to the passage of the Hatch Act of 1939,[10] the postmaster general was in charge of the governing party's patronage and was a powerful position which held much influence within the party, as exemplified by James Farley's tenure from 1933 to 1940 under Franklin D.

[11] After the spoils system was reformed, the position remained a Cabinet post, and it was often given to a new president's campaign manager or other key political supporters, including Arthur Summerfield, W. Marvin Watson, and Larry O'Brien, each of whom played important roles organizing the campaigns of presidents Dwight Eisenhower, John F. Kennedy, and Lyndon B. Johnson, respectively, and was considered something of a sinecure.

Poet and literary scholar Charles Olson, who served as a Democratic National Committee official during the 1944 U.S. presidential election, declined the position in January 1945.

In 1971, the Post Office Department was re-organized into the United States Postal Service, an independent agency of the executive branch, and the postmaster general was no longer a member of the Cabinet[12] nor in line of presidential succession.