Presidents Abraham Lincoln and Harry S. Truman were the only U.S. Presidents to also be Postmasters. However, there is a difference between Lincoln and Truman’s appointments as Postmasters – only Lincoln actually preformed the duties himself, whereas Truman held the title but assigned the position to someone else.

While residing in New Salem, Illinois, Abraham Lincoln was appointed as the town’s Postmaster on May 7, 1833 when he was only 24-years-old. Mail was delivered to the post office only once a week and residents would come and pick up their mail. If, for whatever reason, a person could not pick it their mail, Lincoln would hand deliver the mail himself. In 1835, he was compensated $55.70 for his work. Lincoln held this position until the post office was relocated on May 30, 1836 to Petersburg.

At the age of 28, future president Harry S. Truman lost his father and took on his responsibilities in addition to working on the family farm. On December 2, 1914, Truman was appointed the Postmaster of Grandview, Missouri (near Kansas City) by Congressman William Borland. According to Truman he only held the title, “I let a [Civil War] widow woman who was helping to raise and educate her younger sisters and brothers run the office as assistant postmaster and take the pay which amounted to about fifty dollars a month — a lot of money in those days. It would have paid two farmhands.” The widow, Ella Hall, held the position until June 17, 1915 when Truman’s successor was appointed as postmaster of the Grandview Post Office.

Source
United States Postal Service, “Postmasters Abraham Lincoln and Harry Truman,” April 2005.