Answer:
William O. Douglas has the distinction of being the longest-serving Supreme Court Justice in history, with a tenure of 36 years, 209 days. He was nominated by President Roosevelt in 1939 and served until his retirement in November 1975.
Douglas was preceded in office by Louis D. Brandeis, the first Jewish member of the Court. He was succeeded by John Paul Stevens, who retired from the bench on June 29, 2010, more than 34 years later.