Teddy Roosevelt, then Harry S. Truman.
Roosevelt because he was just so, well I can't think of another word besides bada$$. He was a man's man. Anything he wanted, he did. In terms of being a president, he probably strengthened the executive branch more so, and more significantly than any other president.
- Need a new shipping lane through Panama to increase US might, but Colombia won't relent? No problem, start a revolution in Panama. Consequently, also became the first president to make a foreign trip.
- European powers messing with the western hemisphere? No problem, reinterpret the Monroe Doctrine.
- Let the Old World know that the US had one very awesome military? No problem, paint a bunch of battleships white and have them sail them around the world. He was also the one who ordered White House to be painted white.
- Avid hunter but notice that good hunting grounds are going away? No problem, become a conservationist. For all the hunters on TFL....
Then there were his feats before and after his presidency.
- There was that charge up a hill we all know about.
- Shot in the chest by some assassin during an election campaign? No problem, suck it up and give your speech, as blood pours down your shirt.
Teddy Roosevelt was no pansy. This guy, on the other hand...