Romanini, 59, of Mayfield, had been charged with bribery Sept. 23.
Federal officials said that Romanini had a new roof put on Russo's house in 2007 after it failed an inspection in April 2007.
Romanini told Russo it would cost $25,000 and sent him an invoice, his attorney Niki Schwartz said, but Russo never paid for the roof and Romanini never pressed for payment.
Some time later, Romanini asked Russo for a pay raise for his relative who worked for Russo. Russo twice raised the salary of Romanini's brother-in-law who worked in the auditor's office.
Romanini is scheduled to be sentenced Jan. 5 and faces up to 14 months in prison. U.S. District Judge John Adams could also choose to place him on home detention.
Adams is also requiring Romanini to pay $15,000 in restitution to Cuyahoga County. That amount is less the $10,000 Romanini got for selling scrap copper taken from the roof.
Some of the materials used on the roof came from Willoughby Supply, which Romanini founded and his family still runs.