(1908–73), 36th president of the US 1963–69; known as LBJ. Before becoming vice president 1961–3, he was a US senator 1949–61. He succeeded to the presidency upon the assassination of President Kennedy and was elected for four more years in 1964. His domestic programs, such as those for civil rights, were labeled the Great Society. During his administration, US involvement in Vietnam increased, undermining his popularity, and he did not seek re-election.