Kaymer, who won his second major title after his 2010 PGA Championship victory finished 72 holes on nine-under 271, the second-lowest total in US Open history.
Americans Rickie Fowler and Erik Compton shared second on 279, each after firing final-round 72s.
Kaymer became only the seventh player to win after leading every round, joining a select champions' list that includes Tiger Woods, Rory McIlroy, Walter Hagen, Ben Hogan, James Barnes and Tony Jacklin.
The 29-year-old from Düsseldorf became the first man from continental Europe to win the US Open crown and the fourth European winner in five seasons.
Kaymer followed his US Open record-low start of back-to-back 65s with a 72 to lead by five entering the last round and then managed his edge to the end.
And if Kaymer's prognostication is as good as his putting, the United States is in big trouble in its World Cup football showdown against Germany.
He predicted his homeland's side would defeat the Americans, coached by German legend Jürgen Klinsmann, by 3-1 when they meet on June 26th in their final first-round Group G match in Brazil.
"I think you are a little bit the underdog," Kaymer said. "USA, you're not as bad as people make you. I wouldn't say you guys have a chance to win the World Cup, but I think it's not a given for Germany. My bet would be 3-1 for Germany."