The United States is a federal constitutional republic, in which the President of the United States (the head of state and head of government), Congress, and judiciary share powers reserved to the national government, and the federal government shares sovereignty with the state governments.


The U.S. government had a “president” before George Washington.
Though George Washington is indisputably the first President of the United States, he technically wasn’t the first person in the federal government with the title of “president.”
Washington was elected under the government formed by the ratification of the U.S. Constitution in 1788 — he even won the v**e unanimously — but the Constitution wasn’t the only government-forming document in the nation’s history.
Ratified in 1781, the Articles of Confederation — the United States’ first constitution — formed what’s known as the Confederation Congress, and this governing body was led by a president who held a one-year term.
AdvertisementThe Confederation Congress was an extension of the Continental Congress that had existed in different forms since 1774 and was renamed after the Articles of Confederation took effect on March 1, 1781. Samuel Huntington of Connecticut was serving as the president of the Continental Congress at the time and became the first president of the new government.
He resigned that July, however, and was succeeded by Thomas McKean of Delaware; McKean himself was replaced when the first new delegates to Congress were chosen on November 5, 1781.
They elected John Hanson, the delegate from Maryland, as the new leader, and he was the first to serve the full year-long term in the role.
Each of these men held the title of “president,” but they didn’t possess the powers of the position that would eventually be enumerated under the U.S. Constitution.
And though they presided over some of the most consequential years in the nation’s history, their contributions were soon eclipsed by Washington’s inauguration in 1789.
https://historyfacts.com/us-history/fact/the-federal-government-had-a-president-before-george-washington/

Center for American Civics
https://civics.asu.edu/civic-literacy-curriculum/section1