The chief of naval operations (CNO) is the highest-ranking officer of the United States Navy. The position is a statutory office held by an admiral who is a military adviser and deputy to the secretary of the Navy. The CNO is also a member of the Joint Chiefs of Staff and in this capacity, a military adviser to the National Security Council, the Homeland Security Council, the secretary of defense, and the president.

The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the world's most powerful navy and the largest by tonnage, at 4.5 million tons in 2021 and in 2009 an estimated battle fleet tonnage that exceeded the next 13 navies combined. It has the world's largest aircraft carrier fleet, with 11 in service, 1 undergoing trials, two new carriers under construction, and six other carriers planned as of 2024. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the U.S. Navy is the third largest of the United States military service branches in terms of personnel. It has 299 deployable combat vessels and about 4,012 operational aircraft as of July 18, 2023.