Why did Hamilton's party become known as the federalist?

Answer 1

Actually there were no parties until Jefferson left Washington's administration to actively undermine Hamilton's economic policies which Washington supported to Jefferson's dismay. By default, because of his energy and ideas, he became the leader of the Federalist philosophy and by association perceived a leader of a party. Hamilton abhorred parties or factions as they called it through the 1780's because he said people will want the party to be successful irrespective if it is best for the country.

Answer 2

Alexander Hamilton was the Father of the Federalist Papers. The first essay was written in October 1788, a month AFTER the U.S. Constitution was adopted by the 39 delegates in Philadelphia. The Federalist supported the ratification of the U.S. Constitution Those that took an opposing view were initially called Anti-Federalists. Many of those leaders united behind Jefferson, initially called the Republican part, then the Democrat-Republican party and then the Democrat party.