Alexander Hamilton (January 11, 1755 or 1757 – July 12, 1804) was an American revolutionary, statesman and Founding Father of the United States. Hamilton was an influential interpreter and promoter of the U.S. Constitution, the founder of the Federalist Party, as well as a founder of the nation's financial system, the United States Coast Guard, and the New York Post newspaper. As the first secretary of the treasury, Hamilton was the main author of the economic policies of the administration of President George Washington. He took the lead in the federal government's funding of the states' American Revolutionary War debts, as well as establishing the nation's first two de facto central banks (i.e. the Bank of North America and the First Bank of the United States), a system of tariffs, and friendly trade relations with Britain. His vision included a strong central government led by a vigorous executive branch, a strong commercial economy, support for manufacturing, and a strong national defense.

Hamilton was born out of wedlock in Charlestown, Nevis. He was orphaned as a child and taken in by a prosperous merchant. When he reached his teens, he was sent to New York to pursue his education. While a student, his opinion pieces supporting the Continental Congress were published under a nom de plume, and he also addressed crowds on the subject. He took an early role in the militia as the American Revolutionary War began. As an artillery officer in the new Continental Army he saw action in the New York and New Jersey campaign. In 1777, he became a senior aide to Commander in Chief General George Washington, but returned to field command in time for a pivotal action securing victory at the Siege of Yorktown, effectively ending hostilities.

After the war, he was elected as a representative from New York to the Congress of the Confederation. He resigned to practice law and founded the Bank of New York before returning to politics. Hamilton was a leader in seeking to replace the weak confederal government under the Articles of Confederation; he led the Annapolis Convention of 1786, which spurred Congress to call a Constitutional Convention in Philadelphia, where he then served as a delegate from New York. He helped ratify the Constitution by writing 51 of the 85 installments of The Federalist Papers, which are still used as one of the most important references for Constitutional interpretation.

Hamilton led the Treasury Department as a trusted member of President Washington's first Cabinet. To this day he remains the youngest U.S. cabinet member to take office since the beginning of the Republic. Hamilton successfully argued that the implied powers of the Constitution provided the legal authority to fund the national debt, to assume states' debts, and to create the government-backed Bank of the United States (i.e. the First Bank of the United States). These programs were funded primarily by a tariff on imports, and later by a controversial whiskey tax. He opposed administration entanglement with the series of unstable French revolutionary governments. Hamilton's views became the basis for the Federalist Party, which was opposed by the Democratic-Republican Party led by Thomas Jefferson and James Madison.

In 1795, he returned to the practice of law in New York. He called for mobilization under President John Adams in 1798–99 against French First Republic military aggression, and became Commanding General of the U.S. Army, which he reconstituted, modernized, and readied for war. The army did not see combat in the Quasi-War, and Hamilton was outraged by Adams' diplomatic approach to the crisis with France. His opposition to Adams' re-election helped cause the Federalist Party defeat in 1800. Jefferson and Aaron Burr tied for the presidency in the electoral college, and Hamilton helped to defeat Burr, whom he found unprincipled, and to elect Jefferson despite philosophical differences.

Hamilton continued his legal and business activities in New York City, and was active in ending the legality of the international slave trade. Vice President Burr ran for governor of New York State in 1804, and Hamilton campaigned against him as unworthy. Taking offense, Burr challenged him to a duel on July 11, 1804, in which Burr shot and mortally wounded Hamilton, who died the following day.

Hamilton is generally regarded as an astute and intellectually brilliant administrator, politician and financier, if often impetuous. His ideas are credited with laying the foundation for American government and finance.