Upon graduation from Harvard, Post took a position with the "Boston American", and in 1933 he applied for a job with Arthur Krock, the head of the "New York Times" Washington bureau, as a junior correspondent. Krock, after telling Post to do it the hard way and work his way up, offered him a position as an office boy running messages for the phone operator. He took it. Post, however, briefly left Washington for New York City, where he worked on Fiorello H. La Guardia's mayoral re-election campaign and, simultaneously, his brother Langdon Ward Post's bid for borough president. After his brother lost, Post returned to Washington.