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, and was part of the group of Kennedy's close advisers dubbed the “Irish Mafia.”