Michael Vincent Forrestal (November 26, 1927 – January 11, 1989) was one of the leading aides to McGeorge Bundy, the National Security Advisor of President John F. Kennedy.

He was seen as a pivotal figure in the changing of U.S. foreign policy, including recommending support for the coup d'état that deposed the first president of South Vietnam, Ngô Đình Diệm.

Following the arrest and assassination of Diệm, which was backed by the Central Intelligence Agency, General Dương Văn Minh assumed the presidency in November, 1963.

Other than his political life, Forrestal was a senior partner in Shearman & Sterling and a legal advisor to the state-owned Algerian oil company, Sonatrach during the 1970s.

He received a commission in the United States Navy, and was appointed an assistant naval attaché in Moscow under W. Averell Harriman, the Ambassador to the Soviet Union.

From 1962 to 1965 Forrestal was a member of the senior staff of the National Security Council, where he specialized in Asian affairs and participated in the deliberations and decisions that led to increased U.S. military presence in Vietnam.

Forrestal, Harriman and Hilsman were prominent among the State Department officials who felt that Diem needed to be removed, and began drafting a response to the raids to send to Ambassador Henry Cabot Lodge Jr.

They were the only senior State Department officials on duty on August 24, 1963, a Saturday afternoon, with Defense Secretary Robert McNamara and CIA director John McCone on vacation.

Kennedy was met with angry comments by Rusk, McNamara, McCone and Chairman of the Joint Chiefs of Staff General Maxwell Taylor, all of whom denied authorizing the cable.