Warren Harding
(1920 to 1923) 

He studied law, sold insurance, and taught school but made his money as publisher of the Marion, Ohio, Daily Star. Harding used the newspaper to launch his political career; ironically, the press had a field day in the mid-1920s when his reputation was sullied by the Teapot Dome oil reserve scandal.

Jimmy Carter
(1977 to 1981) 

A pioneer in the nuclear-powered Navy, Carter left the military to run his family's peanut-farm in Georgia. After leaving the White House, he was forced to sell the operation, which had foundered due to poor management and a drought. Inflation and unemployment dogged his presidency.

Herbert Hoover
(1929 to 1933) 

Hoover was a successful mining engineer before he started a consulting firm and became known as the Doctor of Sick Mines. He was no doctor of sick economies, however. His handling of the Great Depression cost him his job in 1932, when he lost to Franklin D. Roosevelt.

George W. Bush
(2001 to present) 

A Harvard M.B.A., Bush was an executive in several West Texas oil concerns that failed to prosper as oil prices tanked in the 1980s. In 1989, he bought a stake in the Texas Rangers baseball team that he later sold for a $14.2 million profit–even as the Rangers traded away slugger Sammy Sosa.