Kenneth P. O'Donnell

Kenneth Patrick O'Donnell (March 4, 1924 – September 9, 1977) was an American political consultant and the special assistant and appointments secretary to President John F. Kennedy from 1961 until Kennedy's assassination in November 1963. O'Donnell was a close friend of President Kennedy and his younger brother Robert F. Kennedy. O'Donnell, along with Larry O'Brien and David Powers, was part of the group of Kennedy's close advisers dubbed the "Irish Mafia."

O'Donnell also served as an aide to President Lyndon B. Johnson from 1963 to 1965. He later served as an adviser to Robert Kennedy's 1968 presidential campaign. In his biography With Kennedy (1966), Pierre Salinger writes:

It was my impression that O'Donnell had the greatest influence in shaping the President's most important decisions. He was able to set aside his own prejudices against individuals and his own ideological commitments (I would rate him a moderate Democrat) and appraise the alternatives with total objectivity. It was impossible to categorize O'Donnell, as White House observers did with other staff members, as either a "hawk" or a "dove" on foreign policy, or a Stevenson liberal or Truman conservative on civil rights. JFK gave extra weight to O'Donnell's opinions because he knew he had no personal cause to argue. Ken had only one criterion: Will this action help or hurt the President? And that, for O'Donnell, was another way of asking: Will it help or hurt the country?