Alex Arshinkoff, 62, an Ohio political boss credited with mentoring a generation of young politicians and helping elect presidents, has died.

Ohio Republican Chair Jane Timken said Mr. Arshinkoff, the Summit County Republican chairman, died Monday.

He was one of the state's most powerful and longest-serving party chairs, a man once credited by former President George W. Bush as the most effective chairman in America.

The Akron Beacon Journal reported that he had been undergoing dialysis for several years and had been in deteriorating health since a 2012 car accident.

Mr. Arshinkoff was viewed by many as a brilliant political tactician. He took over the small county party in northeastern Ohio at 23 and turned it into a fund-raising dynamo that gave millions of dollars to candidates.

Timken called Mr. Arshinkoff an "icon."