Robert McDonald wanted to enroll in West Point long before he legally could. In fact, at 11 years old, he wrote his local Congressman asking for a recommendation to the school. Though that didn't pan out immediately, McDonald did enroll when he hit the legal age. He graduated in the top 2% of his class with a B.S. in engineering in 1975.
Though he could have joined the Army Corps of Engineers, McDonald joined the infantry instead. He told Fortune in 2009, "I figured -- and this is the story of my life, really, if you're gonna be in the Army, go into the infantry. If you're going to be in marketing, work for P&G. You don't do things halfway."
And indeed, in 1980, right after he got out of the military, McDonald started working in P&G's marketing division. He climbed to the top of the company, becoming CEO in 2009.