Lyndon Baines Johnson, 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.