Cave Johnson was an American politician who served the state of Tennessee as a Democratic congressman in the United States House of Representatives. Johnson was the 12th United States Postmaster General in the administration of James K. Polk from 1845 to 1849.

The United States postmaster general (PMG) is the chief executive officer of the United States Postal Service (USPS). The PMG is responsible for managing and directing the day-to-day operations of the agency.