U.S. District Senior Judge William J. Nealon of the Middle District of Pennsylvania has died at the age of 95, just days after becoming the longest-sitting U.S. district court judge in history.

Nealon died Thursday morning, according to a statement from Middle District Chief Judge Christopher Conner. Nealon has served on that court for more than 55 years, since December 1962, when he was appointed by President John F. Kennedy.

As of Tuesday, he broke the record of federal Judge Henry Potter, who served on the U.S. District Court for the District of North Carolina from 1802 to 1857.

“Judge Nealon was an esteemed colleague, who showed, through the example of his life, the meaning of integrity, compassion and public service. He was a role model and mentor to countless judges, lawyers and court personnel,” Conner said in a statement Thursday. “While his loss is immeasurable, our court family will be forever enriched by Judge Nealon's extraordinary contributions to the United States District Court for the Middle District of Pennsylvania.”

Nealon served as chief judge on the court from 1976 until 1989, when he assumed senior status. Before he was appointed to the Middle District, he was a judge on the Lackawanna County Court of Common Pleas from 1960 to 1962. He worked as a lawyer in private practice from 1951 to 1960.

The federal courthouse in Scranton bears his name, the William J. Nealon Federal Building and U.S. Courthouse.

According to a recent report by the Times-Tribune, Nealon had planned to retire, choosing not to seek certification as a senior judge after Sept. 30 of this year.

Nealon and his wife, Jean, had 10 children, including Lackawanna County Judge Terrence R. Nealon and lawyer Tom Nealon.