Olin Johnston (November 18, 1896 - April 18, 1965) was a Democratic Party politician from the U.S. State of South Carolina. He represented South Carolina in the United States Senate from 1945 until 1965.
Johnston was born near Honea Path, South Carolina. Johnston graduated from Wofford College and served in the United States Army during World War I. Johnston was elected to the South Carolina House of Representatives as a Democrat in 1923, serving for one year. He was elected to the same body in 1927 and served until his unsuccessful campaign for Governor in 1930.
Johnston was elected Governor of South Carolina in 1934, serving for one term. After highway commissioners appointed by previous governors refused to leave their posts, Johnston mobilized the National Guard to occupy the offices of the Highway Department.
After one term, Johnston was unable to run for re-election in 1938, so he unsuccessfully ran against "Cotton Ed" Smith for the United States Senate. Johnston then ran for the Senate in 1941 to replace James F. Byrnes, losing to Burnet R. Maybank.
Johnston was elected Governor of South Carolina again in 1942, serving until his resignation on January 3, 1945. During his second term, Johnston signing laws which circumvented the Smith v. Allwright decision in an attempt to make the Democratic Party a private organization.
Johnston was elected to the Senate in 1944, defeating "Cotton Ed" Smith. Johnston was re-elected three times, serving in the Senate until his death in 1965. He served for several years as Chairman of the now defunct Post Office Committee. Johnston was not as conservative as most other Senators from the Deep South, retaining a populist position on many economic issues. Unlike most Southern Democrats, Johnston opposed the anti-union Taft-Hartley labor law in 1947 and he voted for both the War on Poverty and Medicare in his last full year in office, 1964. However, like all other politicians from the Deep South during this period, Johnston was orthodox on the "race question", opposing all civil rights legislation.
While not a prominent figure nationally, Johnston was very well-entrenched in his home state. He may be the only Senator to have defeated two future Senators. He retained his seat despite challenges from Strom Thurmond in the Democratic primary in 1950 and Ernest Hollings in the 1962 primary. In both cases Johnston was the more liberal candidate. Hollings, then serving as Governor, attacked the Senator as "the tool of the Northern labor bosses", yet Johnston defeated him by a 2-1 margin.