"At the end of my third year, I had marched enough extra duty to take me to Baltimore and back 17 times," he said.
Despite the resistance, McCain did learn discipline there - discipline he now applies to his presidential campaign. Wednesday he told reporters he's put together a list of about 20 possible running mates but refuses to name any of them.
"It takes weeks, if not months, to just go through the background," he said.
But a more pressing problem for McCain now is money. A new non-partisan report shows the two Democratic candidates have raised nearly $50 million from business interests that usually give to Republicans. McCain has raised only $13 million.
"He has frankly angered, alienated business interests over his many years in Congress," Stuart Rothenberg of The Rothenberg Political Report said.
But McCain insists the fundraising operation is now back on track, and so is his sense of humor. Last night he appeared on David Letterman's show.
But late night TV aside, McCain's aides say he's focused on winning - another quality he was taught at the Naval Academy.
McCain graduated from the Naval Academy near the very bottom of his class, and some were surprised he graduated at all. Wednesday he said the fact that he is now a candidate for president shows that in America, anything is possible.