Which Supreme Court justice has served the longest tenure in history?
After the retirement of Justice Louis Brandeis, Yakima, Washington, native William Orville Douglas was nominated by friend Franklin Roosevelt. At 40 years old he was the second youngest Supreme Court justice in U.S. history, and he would serve for the next 36 years, 209 days from April 17, 1939 to November 12, 1975.
Longtime Chief Justice Earl Warren said that Douglas possessed "the nearest thing to genius I've ever seen."
—The Fact Monster