Lyndon Baines Johnson (; August 27, 1908 – January 22, 1973), also known as LBJ, was the 36th president of the United States, serving from 1963 to 1969. He became president after the assassination of John F. Kennedy, under whom he had served as the 37th vice president from 1961 to 1963. A Southern Democrat, Johnson previously represented Texas in Congress for over 23 years, first as a U.S. representative from 1937 to 1949, and then as a U.S. senator from 1949 to 1961.

Born in Stonewall, Texas, Johnson worked as a teacher and a congressional aide before winning election to the U.S. House of Representatives in 1937. In 1948, he was controversially declared the winner in the Democratic primary for the U.S. Senate election in Texas before winning the general election. He became Senate majority whip in 1951, Senate Democratic leader in 1953 and majority leader in 1954. Senator Kennedy bested Johnson and his other rivals for the 1960 Democratic presidential nomination before surprising many by offering to make Johnson his vice presidential running mate. The Kennedy–Johnson ticket won the general election. Vice President Johnson assumed the presidency in 1963, after President Kennedy was assassinated. The following year, Johnson was elected to the presidency in a landslide, winning the largest share of the popular vote for the Democratic Party in history, and the highest for any candidate since the advent of widespread popular elections in the 1820s.