PHOENIX — Former U.S. Sen. Jon Kyl, the Arizona Republican who spent nearly three decades in Congress and briefly returned to the Senate after John McCain’s death, has died at 84.

Kyl died Wednesday night from complications of a neurological disease, his family said in a statement carried Thursday by Arizona outlets including KJZZ and AZFamily. Family friend Gordon James told AZFamily and the Associated Press that Kyl died of a neurological disorder; Kyl had withdrawn from public life in December 2025 after announcing a dementia diagnosis.

“We know that Jon belonged to all of Arizona, a state he loved and explored with vigor, curiosity, and wonder. Serving his state and nation in Congress was a privilege and responsibility he honored and respected. We are grateful for his full and meaningful public life,” the family said, according to KJZZ.

Born April 25, 1942, in Oakland, Nebraska, Kyl grew up in Iowa, then moved to Arizona for the University of Arizona, where he earned a law degree and met his wife, Caryll. Before Congress he helped shape Arizona’s 1980 groundwater code as a utility lawyer. He served in the U.S. House from 1987 to 1995 and in the Senate from 1995 to 2013, rising to Republican whip in his final full term. Former Gov. Doug Ducey appointed him in 2018 to finish McCain’s term; Kyl served less than four months before returning to lobbying.

Arizona leaders across the aisle issued condolences Thursday. Ducey called Kyl a “giant” in the Senate and a mentor. Gov. Katie Hobbs said Arizonans were mourning “a dedicated statesman who always cared deeply for our state.” Former Sen. Jeff Flake wrote that Arizona had “lost a giant.” Memorial services will be announced later.

Sources