Who is in charge of the USA today?

Could you please clarify who exactly holds the highest executive authority and oversees the operations of the United States government today? Is it the President, who is elected by the people and serves as the head of state and commander-in-chief of the armed forces? Or is there another individual or entity within the government structure that ultimately wields the most power and responsibility for leading the nation? Understanding the current hierarchy and chain of command is crucial for grasping the overall structure and functioning of the American political system.