Madison's Virginia Plan was the basis for the convention's deliberations, and he was an influential voice at the convention. He became one of the leaders in the movement to ratify the Constitution and joined Alexander Hamilton and John Jay in writing The Federalist Papers, a series of pro-ratification essays that remains prominent among works of political science in American history. Madison emerged as an important leader in the House of Representatives and was a close adviser to President George Washington.

Madison was elected president in 1808. Motivated by desire to acquire land held by Britain, Spain, and Native Americans, and after diplomatic protests with a trade embargo failed to end British seizures of American shipped goods, Madison led the United States into the War of 1812. Although the war ended inconclusively, many Americans viewed the war's outcome as a successful "second war of independence" against Britain. Madison was re-elected in 1812, albeit by a smaller margin. The war convinced Madison of the necessity of a stronger federal government. He presided over the creation of the Second Bank of the United States and the enactment of the protective Tariff of 1816. By treaty or through war, Native American tribes ceded 26,000,000 acres of land to the United States under Madison's presidency.

Retiring from public office at the end of his presidency in 1817, Madison returned to his plantation, Montpelier, and died there in 1836.