Washington's military career had a rocky start. As the leader of a force that was supposed to help protect British settlers in the Ohio region from the French, the young Washington led an attack against a small group of French soldiers that—oops—included a French envoy (or ambassador).
This is a big no-no in international relations. It led to some serious tension between the French and the English, and it helped kick-start the French and Indian War. It also made Washington a hero in many British colonists' eyes (source).
Washington resigned from the military pretty soon after the French and Indian (a.k.a. Seven Years') War started, so he wasn't hugely involved.
However, this war was one of the main reasons for the changes in taxation that led to the American Revolution, so it's a pretty big deal in colonial history. Basically, the British had to make more money off the colonies to pay for the war that was theoretically fought to protect the colonies.
There's obviously a lot to know about the American Revolution. Besides the United States, you know, being created, the war also made George Washington a national hero.
His success in keeping up morale and the fight until the British gave out made him, in many people's eyes, the obvious choice to be the first president.
Washington really, really wanted to retire after the end of the American Revolution. He was so set on it, he wrote a farewell letter to be read all over the new United States to soldiers by commanders. It was the first of several farewell addresses he would prepare.
The birth of political parties in the United States can, in some ways, be traced back to approximately this moment. The fact that The Federalist Papers were published to argue for a strong central government shows us that there was a definite opposing viewpoint that the authors (James Madison and Alexander Hamilton, mostly) needed to argue against.
The Articles of Confederation that were supposed to form the newly independent America's government weren't really doing their job. So, once again, a bunch of guys met to figure out a different strategy.
They emerged a couple of years later with the Constitution of the United States, which, among other things, established the position of president of the United States.
It took a while to get the Constitution written and ratified (i.e., approved), but we got there eventually.
If you give a country a constitution, they're going to want a president. Washington reluctantly made his way to New York City, then the capital of the nation, to take up his new role as the very first president of the United States of America (source).
Not surprisingly (if you've read anything about Washington), he did not want to serve a second term. But his people needed him, so he grudgingly agreed to stay on. Once again, he was unanimously chosen by the Electoral College, which hasn't yet happened again (source).
Washington makes a big thing in his farewell address about political parties and how they're a bad thing. Well, that's because right from the get-go, parties started forming in American politics.
Thomas Jefferson and James Madison created the first opposition party—meaning it wasn't the party in power—because they didn't agree with the Federalists about how much power the central government should have. More than 200 years later, this is still one of the biggest questions in American politics.
The big foreign conflict that got Washington and the United States all hot and bothered was the war between Britain and France that broke out a few years after the French Revolution. The causes are complex and related to centuries of Anglo-French political history, but the short version is that the French Revolution caused a major political change and threatened the political situation in Europe overall (source).
Both British and French ships started to interfere with American ones, which is how the United States got pulled into the fray.
Washington talks a lot about America's relationship to other countries. This was largely inspired by the constant debate in Congress over whether the United States should favor a friendship with Great Britain or France, who were at war at the time.
French minister Edmond Charles Genêt, known as "Citizen Genêt" started using U.S. ports to seize British ships, and Washington was not pleased when he found out. He made sure Genêt lost his job and officially proclaimed neutrality in the whole Britain-versus-France kerfuffle.
In 1792, Alexander Hamilton finally put some taxes into effect because the central government needed, you know, money to function. The most unpopular tax was one on alcohol, which is maybe not so surprising given how the colonists had reacted to the Tea Act.
Finally, the objections to the law got violent, and Washington had to put them down with the national militia. It wasn't all sunshine and daisies during Washington's presidency.
Finally, poor George Washington got to retire. For a few years, at least.
But not before addressing the growth of partisan politics and international relations during his presidency. It was a good effort, at any rate. Originally published in the American Daily Advertiser, the address was published all over the country—since TV wouldn't exist for another 150 years or so.
For some reason, people needed a morale boost in 1862—oh, right, it was the middle of the Civil War, so maybe that's the reason.
Anyway, people in Philadelphia petitioned to have Washington's farewell address read aloud in the Senate chamber to commemorate the 130th anniversary of Washington's birthday (source).
Every year on Washington's birthday, the farewell address is read aloud in the Senate by a chosen member of alternating parties. The practice continues today (source).