Ulysses S. Grant

The general who helped the North win the American Civil War was working in his father's leather store (in Galena, Illinois) when the fighting began. Despite his military education, he didn't want to be a soldier - he wanted to become a math professor.

According to the White House biography about him:  "He was appointed by the Governor to command an unruly volunteer regiment. Grant whipped it into shape and by September 1861 he had risen to the rank of brigadier general of volunteers."

Grant's rise from clerk, to commanding General of the Armies, to President of the United States took seven years.