George Washington was an important figure in history for many reasons! He played a significant role in the American Revolutionary War and was Commander in Chief of the Continental Army. It was under his guidance that the Continental Army defeated the British at Yorktown and the United States successfully won its independence from Britain.
Perhaps most important was his post-war role as the first president of the United States. Washington set the critical precedent of the US president only serving two terms which was new considering that the United States had just rid itself of a king. He is also responsible for the presidential customs we have now (inaugural addresses, addresses to congress, and the cabinet system). As president Washington opposed the formation of political parties (he considered them divisive) but nonetheless the Federalists and Jeffersonian Republicans emerged during his presidency.
Washington also declared American neutrality in the French Revolutionary Wars which emerged as a product of the French Revolution.
This is a very abridged version as Washington was a towering figure of American history but I hope this provides some insight!