Justice Clarence Thomas has become the fourth-longest-serving justice in U.S. Supreme Court history as of Thursday.
Thomas reached 12,572 days on the bench—34 years and 153 days—moving past Chief Justice John Marshall, according to tenure calculations based on his October 23, 1991, commission date.
The milestone comes just months after Thomas moved into fifth place, surpassing Justice Hugo Black in November 2025, as previously reported by The Dallas Express. At that time, Thomas had logged 12,448 days and trailed only four justices in total tenure.
Now ranked fourth, Thomas sits behind Justices William O. Douglas, Stephen Johnson Field, and John Paul Stevens. He will not surpass another justice for around a month and a half, but is expected to leapfrog two positions within a three-day span later this year, putting him within reach of the top spot. From there, Thomas would enter a roughly two-year stretch during which he could become the longest-serving justice in American history if he remains on the Court.
Thomas has not publicly indicated an intent to step down.
Marshall, whom Thomas has now surpassed, is widely regarded as the most influential chief justice in U.S. history. Serving from 1801 to 1835, Marshall helped establish the Supreme Court as a coequal branch of government and authored the landmark opinion in Marbury v. Madison, which established the principle of judicial review.
Thomas has frequently cited Marbury in his own writings and speeches to emphasize the judiciary’s constitutional role. In a 2019 concurrence, he wrote, “That ‘Power’ [judicial Power] is—as Chief Justice Marshall put it—the power ‘to say what the law is’ in the context of a particular ‘case’ or ‘controversy’ before the court. Marbury v. Madison, 1 Cranch 137, 177 (1803).”
In a 1999 speech to the Federalist Society, Thomas quipped, “As Chief Justice John Marshall once declared: ‘The greatest scourge an angry heaven ever inflicted upon an ungrateful and sinning people was an ignorant, a corrupt, or a dependent judiciary.'”
During the Court’s current term, Thomas has continued to author consequential opinions. In United States Postal Service v. Konan, decided February 24, 2026, he wrote the 5-4 majority opinion holding that the Postal Service retains sovereign immunity for claims involving intentional nondelivery of mail.
More recently, in Cox Communications, Inc. v. Sony Music Entertainment, decided March 25, 2026, Thomas authored a unanimous opinion rejecting contributory copyright liability for an internet service provider based solely on user infringement.
Thomas, 77, was appointed by President George H.W. Bush and remains the Court’s longest-serving current member. Over more than three decades, his jurisprudence has touched on issues ranging from administrative law to constitutional interpretation, with his opinions often revisiting foundational questions about the separation of powers.
While Thomas’s tenure milestone marks a historic advancement, the timeline ahead will determine whether he ultimately surpasses Douglas, who holds the record at 36 years and 209 days.
