Harvard president-very-nearly-elect Lawrence H. Summers huffed hurriedly down the concourse toward the United terminal, coattails flapping as he went. It was 7:15 a.m., March 11, and the doors to the tarmac were about to snap shut for departure.

Flight 7736, service from Dulles Airport in Washington, D.C. to Newark, New Jersey—a pumpkin ride for what some might have called an unlikely Cinderella. But instead of picking himself up out of the ashes, Larry Summers was just switching castles.

“That was close,” Summers muttered with a nod in my direction.

As the plane taxied down the runway, Larry Summers was an hour and 38 minutes out of Newark, and only a few minutes more from Rockefeller Center, where he would sell a roomful of Harvard Overseers on his plans for castle number two: The World’s Greatest University.

The man with a reputation for one of the World’s Greatest Egos is calm and confident.

He has a brief presentation planned, he says, but he isn’t overly concerned. He quizzes me on my short Harvard experience, providing a glimpse of what’s on his mind—advising, Faculty contact, facilities—even the Progressive Student Labor Movement. He sips his signature drink: a Diet Coke. A Nutri-Grain bar goes uneaten.

When he wanders off the plane, no one is waiting with signs that say Mr. Summers, or Mr. Harvard President. This man could be anyone. He’s 46 years old, the father of three, soon to be separated from his wife. He loves to play tennis, works long hours and is on the brink of a career change.

He’s also already been the Secretary of the United States Treasury, a fellow at the Brookings Institution, a vice president of the World Bank, the youngest-ever tenured Harvard economics professor and a graduate of the Massachusetts Institute of Technology. And he’s about to slap one final line onto an already colossal resume.