Trivia: Which justice spent the most years on the Supreme Court?
Clarence Thomas
William H. Rehnquist
William O. Douglas
John Marshall
The correct answer is William O. Douglas
So why is this answer correct? : John Marshall was the longest-serving chief justice, holding his position for 34 years, five months, and 11 days between 1801 and 1835. However, the longest-serving justice overall was William O. Douglas from Connecticut. Appointed by Franklin D. Roosevelt in 1939, Douglas served until 1975, a record 36 years, seven months, and eight days. Clarence Thomas is the longest-serving current justice, as he was appointed in 1991.