Johnson took the office in November 1963 following the assassination of his predecessor , John F. Kennedy . He easily defeated a primary challenge by segregationist Governor George Wallace of Alabama to win nomination to a full term . At the 1964 Democratic National Convention , Johnson also won the nomination of his preferred running mate , Senator Hubert Humphrey of Minnesota . Senator Barry Goldwater of Arizona , a leader of his party 's conservative faction , defeated moderate Governor Nelson Rockefeller of New York and Governor William Scranton of Pennsylvania at the 1964 Republican National Convention
assassination of his predecessor
Assassination of John F. Kennedy
1964 United States presidential election