The First Party System was the political party system in the United States between roughly 1792 and 1824. It featured two national parties competing for control of the presidency, Congress, and the states: the Federalist Party, created largely by Alexander Hamilton, and the rival Jeffersonian Democratic-Republican Party, formed by Thomas Jefferson and James Madison, usually called at the time the Republican Party (which is distinct from the modern Republican Party).

The Federalists were dominant until 1800, while the Republicans were dominant after 1800. Both parties originated in national politics, but soon expanded their efforts to gain supporters and voters in every state. The Federalists, successors to the Pro-Administration faction that favored Washington's policies, appealed to the business community and had their base in the North, while the Republicans, like the Anti-Administration faction before them, relied on the planters and farmers within their base in the South and non-coastal North. By 1796, politics in every state was nearly monopolized by the two parties, with party newspapers and caucuses becoming effective tools to mobilize voters.

The Federalists promoted the financial system of Treasury Secretary Hamilton, which emphasized federal assumption of state debts, a tariff to pay off those debts, a national bank to facilitate financing, and encouragement of banking and manufacturing. The Republicans, based in the plantation South, opposed strong executive power, were hostile to a standing army and navy, demanded a strict reading of the Constitutional powers of the federal government, and strongly opposed the Hamilton financial program. Perhaps even more important was foreign policy, where the Federalists favored Britain because of its political stability and its close ties to American trade, while the Republicans admired France and the French Revolution. Jefferson was especially fearful that British aristocratic influences would undermine republicanism. Britain and France were at war from 1793 to 1815, with only one brief interruption. Official American policy was neutrality, with the Federalists hostile to France, and the Republicans hostile to Britain. The Jay Treaty of 1794 marked the decisive mobilization of the two parties and their supporters in every state. President George Washington, while officially nonpartisan, generally supported the Federalists and that party made Washington their iconic hero.

The First Party System ended during the Era of Good Feelings (1816–1824), as the Federalists shrank to a few isolated strongholds and the Democratic-Republicans lost unity. Between 1824 and 28, as the Second Party System emerged, the Democratic-Republican Party split into the Jacksonian faction, which became the modern Democratic Party in the 1830s, and the Henry Clay faction, which was absorbed by Clay's Whig Party.

Leading nationalists, George Washington, Alexander Hamilton and Benjamin Franklin (see Annapolis Convention), called the Constitutional Convention in 1787. It drew up a new constitution that was submitted to state ratification conventions for approval, with the old Congress of the Confederation also approving the process. James Madison was the most prominent figure in the Constitutional Convention; he is often referred to as "the father of the Constitution".

An intense debate on ratification pitted the "Federalists", who supported the Constitution and were led by Madison and Hamilton, against the "Anti-Federalists", who opposed the new Constitution. The Federalists won and the Constitution was ratified. The Anti-Federalists were deeply concerned about the theoretical danger of a strong central government (like that of Britain) that someday could usurp the rights of the states. The Anti-Federalist argument influenced the drafting and eventual passage of the Bill of Rights, which the Federalists agreed to add to the Constitution.

At first, there were no parties in the nation. The framers of the Constitution did not want or expect political parties to emerge because they considered them divisive. However, during the presidency of George Washington, factions soon formed around dominant personalities such as Alexander Hamilton, the Secretary of the Treasury, and Thomas Jefferson, the Secretary of State, who opposed Hamilton's broad vision of a powerful federal government. Jefferson especially objected to Hamilton's flexible view of the Constitution, which stretched to include a national bank. Jefferson was joined by Madison in opposing the Washington administration, leading the "Anti-Administration party"; Hamilton led the informal political faction known as the "Pro-Administration party". Washington was re-elected without opposition in 1792.

Hamilton built a national network of supporters that emerged about 1792–93 as the Federalist Party. This was a somewhat different coalition from the previous Federalist group, consisting of supporters of the Constitution in 1787–1788 as well as entirely new elements, and even a few former opponents of the Constitution (such as Patrick Henry). In response, Jefferson and Madison built a rival network of supporters in Congress and in the states. Madison, who largely authored the Constitution, was a Federalist in 1787–1788, but he opposed the program of the Hamiltonians and their new Federalist Party. The group led by Jefferson and Madison emerged in 1792–93 as the Democratic-Republican Party, which included many former Anti-Federalists.