The Office of United States Director of Central Intelligence (DCI) was the head of the American Central Intelligence Agency from 1946 to 2005, acting as the principal intelligence advisor to the President of the United States and the United States National Security Council, as well as the coordinator of intelligence activities among and between the various U.S. intelligence agencies (collectively known as the Intelligence Community from 1981 onwards).
The office existed from January 1946 to April 21, 2005, and was replaced on that day by the Director of National Intelligence (DNI) as head of the Intelligence Community and the Director of the Central Intelligence Agency (D/CIA) as head of the CIA.
The post of DCI was established by President Harry Truman on January 23, 1946, with Admiral Sidney Souers being the first DCI, followed by General Hoyt Vandenberg who served as DCI from June 1946 to May 1947. The DCI then ran the Central Intelligence Group (CIG), a predecessor of the CIA. The office of DCI thus predates the establishment of the Central Intelligence Agency. The CIA was created by the National Security Act of 1947, which formally defined the duties of the Director of Central Intelligence. This 1947 Act also created the National Security Council.
Until April 2005, the DCI was often referred to colloquially as the "CIA Director," even though he was head of both the CIA and the broader Intelligence Community. After the September 11, 2001, terrorist attacks on the United States and the subsequent investigation by the 9/11 Commission, a movement grew to re-organize the Intelligence Community. That movement prompted the passage of the Intelligence Reform and Terrorism Prevention Act in December 2004, which split the DCI's duties among two new offices. The Office of the Director of National Intelligence (DNI) would serve as head of the Intelligence Community and advise the NSC on intelligence matters. The Director of the Central Intelligence Agency would serve as chief administrator of the CIA.