Alexander Hamilton had a profound impact on the early United States government through his roles as a revolutionary soldier, politician, and the first Secretary of the Treasury. He fought in the American Revolution and was a trusted aide to George Washington. As one of the key Federalists, Hamilton advocated for a strong central government and played a pivotal role in the ratification of the U.S. Constitution. In 1789, Hamilton was appointed as the first Secretary of the Treasury, where he established important financial institutions and policies that helped shape the American economy.