McGeorge Bundy (1919-1996) was Assistant to the President for National Security Affairs in the Kennedy and Johnson Administrations between 1961-1966. He was intensely involved in the Cuban Missile Crisis and the Vietnam War. He was the younger brother of William Bundy, also an official in these administrations.
Bundy was very much of the sort of academic personality that Kennedy liked. In the 1960 campaign, while he considered himself a Republican, while Harvard Dean of Faculty, he was "disillusioned with Nixon and organized support for Kennedy among academics and scientists"  Kennedy had considered appointing him Secretary of State, but decided he was too young; he had become dean at Harvard at the age of 34. H.R. McMaster described him as both being "effusive and engaging" in social settings but having an "abruptness and imperious demeanor with those he considered his intellectual inferiors."
In an oral history interview, Bundy described his understanding of Johnson, while still Vice President, as "...a man of formidable intelligence;...he's a loner; ... when he asks for help, we try and give it to him, but the kind of help he seems to want is more surface than substance." Robert McNamara, who, as Secretary of Defense, said Johnson considered Bundy one of his "Wise Men" advisors, even after he left the White House. 
While Dwight D. Eisenhower's military experience made him comfortable in using formal staff organizations, Kennedy disliked large structures and deemphasized the National Security Council system in favor of ad hoc groups; Bundy often assembled and coordinated such task forces.
The Kennedy process significantly excluded the Joint Chiefs of Staff from the review structure, but he assigned them considerable blame for the failure of the Bay of Pigs invasion. U.S. participation came through the Central Intelligence Agency, reporting to the Kennedy White House.
- Biographies & Profiles: McGeorge Bundy, John F. Kennedy Presidential Library & Museum
- McMaster, H. R. (1997), Dereliction of Duty: Lyndon Johnson, Robert McNamara, the Joint Chiefs of Staff, and the Lies That Led to Vietnam, Harpercollins, p. 4
- Mullholan, Paige E. (January 1, 1969), Oral History Interview with McGeorge Bundy, Interview 1, p. I-7
- Robert S. McNamara (1995), In Retrospect: the Tragedy and Lessons of Vietnam, Times Books division of Random House, p. 348