Final answer:
George Washington was the first president of the United States under the Constitution, inaugurated on April 30, 1789. There was no president under the Articles of Confederation, as this role was created with the Constitution. Washington's leadership helped define the presidency and unify the nation.
Step-by-step explanation:
The first president of the United States under the Constitution was George Washington, who took his oath of office on April 30, 1789, after arriving triumphantly in New York City, which at that time was the nation's capital. The Electoral College had unanimously chosen Washington as the nation's leader, reflecting the immense trust and confidence the American public had in his character and leadership. It is important to note that the Articles of Confederation (AOC), which preceded the Constitution, did not have a singular executive leader akin to a president, and the position as we understand it today was established only with the Constitution and Washington's subsequent election.
Washington's inauguration marked the beginning of the new government under the federal Constitution, after New Hampshire became the ninth state to ratify it in June 1788, bringing it into effect. He served as a symbol of unity and was instrumental in shaping the role of the president, promoting patriotism, internal improvements, the post office, and the idea of a national university. His vice president was John Adams, who was from Massachusetts, symbolizing national unity along with Virginia's Washington.