On Friday, the Democrat from Michigan will have served 57 years, five months, and 26 days, breaking the record held by the late Sen. Robert Byrd of West Virginia.
Dingell’s office tells CNN that the congressman plans a quiet lunch with family and friends, with larger celebrations planned for next week.
President Barack Obama congratulated Dingell in a statement Friday morning, saying the congressman has worked “tirelessly” for his constituents.
“Michelle and I send our warmest wishes to John and his family, and I look forward to congratulating him in person at the White House next week,” he said.
House Speaker John Boehner said he was honored to call Dingell “a good friend.”
“Today belongs to John Dingell, one of the greats and the very definition of a man of the House,” Boehner said in a statement. “His devotion to his constituents and his country, the many battles he’s fought and won on behalf of the American people, and the sheer joy he takes in his work have made him synonymous with this institution.”