The longest-serving Supreme Court justice in U.S. history is William O. Douglas, who held his seat for 36 years and 209 days, from 1939 to 1975. Three others have cleared 34 years on the bench: Stephen Johnson Field, John Paul Stevens, and Hugo Black. Among Chief Justices specifically, John Marshall leads with roughly 34 years of service. Clarence Thomas, who joined the Court in 1991, is the current sitting justice closest to that company.
William O. Douglas: 36 Years, 209 Days
President Franklin D. Roosevelt nominated Douglas in 1939 to fill the seat left by Louis Brandeis, and the Senate Judiciary Committee approved him unanimously.1Federal Judicial Center. Douglas, William Orville He was 40 years old. That early arrival is the single biggest reason his record has stood for half a century.
Over 36 years on the bench, Douglas participated in thousands of cases and became one of the most prolific opinion writers in the Court’s history. His tenure stretched across eight presidential administrations, from the buildup to World War II through the aftermath of Watergate. He championed expansive interpretations of free speech and privacy, which made him a polarizing figure, but a lifetime seat insulated him from the critics.
On December 31, 1974, Douglas suffered a severe stroke that left him partially paralyzed. He tried to return to work, but his health had deteriorated past what the job required. He submitted his retirement letter on November 12, 1975, ending the longest tenure in Court history.2Wikipedia. List of United States Supreme Court Justices by Time in Office
The Others Past 34 Years
Stephen Johnson Field (1863–1897)
Nominated by Abraham Lincoln, Field served approximately 34 years and 9 months, placing him second on the all-time list. His tenure spanned Reconstruction and the rapid industrialization of the late nineteenth century.3Federal Judicial Center. Field, Stephen Johnson
John Paul Stevens (1975–2010)
Stevens took his seat just weeks after Douglas retired, creating an unusual back-to-back run of marathon tenures in the same chair. He served roughly 34 years and 6 months and retired at age 90, ranking third all-time.2Wikipedia. List of United States Supreme Court Justices by Time in Office
Hugo Black (1937–1971)
Appointed by FDR two years before Douglas, Black served about 34 years and one month. The two overlapped for most of Black’s tenure, and Black was a forceful advocate for applying the Bill of Rights to state governments.
The Longest-Serving Chief Justice: John Marshall
Among Chief Justices, John Marshall holds the record by a wide margin. He led the Court for about 34 years, from 1801 until his death in 1835.2Wikipedia. List of United States Supreme Court Justices by Time in Office His tenure was foundational: he established the principle of judicial review in Marbury v. Madison and transformed the Court from a relatively weak institution into a co-equal branch of government. No Chief Justice since has come close to his length of service.
Clarence Thomas and the Current Court
Clarence Thomas is the sitting justice closest to the top of the all-time list. He joined the Court on October 23, 1991, at age 43.4Supreme Court of the United States. Current Members By 2026, he will have served roughly 35 years, putting him in the same neighborhood as Field, Stevens, and Black. Whether he challenges Douglas’s record depends on how long he stays.
Why Appointment Age Is the Biggest Factor
Reaching 30 years on the Court is not unusual for justices who arrive young and stay healthy. Douglas was 40 when he joined. Joseph Story, the youngest person ever appointed, was 32 when President James Madison nominated him in 1811, and he went on to serve 33 years. Thomas was 43. Presidents understand this math, and it creates a strong incentive to nominate candidates in their 40s or early 50s rather than distinguished older jurists who might serve only a decade.
Why Justices Can Stay So Long
The constitutional foundation for these tenures is Article III, Section 1, which says federal judges hold their offices “during good Behaviour.”5Congress.gov. U.S. Constitution – Article III A justice faces no built-in expiration date. As long as their conduct doesn’t rise to the level of an impeachable offense, they can serve for life.
The framers designed it this way deliberately. They wanted judges who could rule based on the law without worrying about political retaliation from the president who appointed them or the Congress that confirmed them. That protection is why appointments made in the Roosevelt administration were still shaping decisions in the Ford administration.
Federal law also gives justices a comfortable off-ramp. Under 28 U.S.C. § 371, a justice can retire or move to senior status with a full salary once their age and years of service add up to at least 80, with a minimum age of 65.6Office of the Law Revision Counsel. 28 Code 17 – Resignation and Retirement of Justices and Judges Justices in senior status keep their salary and title and can be assigned to sit on lower federal courts.7Federal Judicial Center. The Evolution of Judicial Retirement The structure rewards staying.
Why the Record Still Matters
The possibility that a single appointment can shape American law for 35 or 40 years has fueled a debate over whether justices should serve fixed terms. The most prominent proposal calls for 18-year terms, with a new vacancy opening every two years so that each four-year presidential term produces two appointments.8Congressman Hank Johnson. Rep. Johnson Re-Introduces Supreme Court Justice Term Limit Measure No such bill has passed either chamber of Congress, and critics argue any real term limit would require a constitutional amendment. For now, Douglas’s 36-year record stands, and the structure that produced it remains in place.