Sinagra admitted bribing former Parma school board member J. Kevin Kelley in exchange for consulting work from the school district.
He also admitted taking $190,000 in fees from Alternatives Agency, a Cleveland halfway house, but performed little or no work for the agency through his consulting company, A.C. Sinagra & Associates.
Sinagra, 69, told O'Malley that he has been hospitalized for an acute anxiety disorder. Federal officials say Sinagra has cooperated with the federal probe into alleged public corruption in Cuyahoga County.
Sinagra faces up to about three years in prison. Sinagra also must reimburse $106,500 to Alternatives Agency and $5,000 to the Parma City School District.
Sinagra, a Republican, served as Lakewood mayor from 1978 until 1990. He became a state senator then until 1994.
The plea deal for Sinagra is for a shorter prison sentence.
Sinagra's lawyer John Brzytwa Jr. declined to comment.
Sinagra was the eighth person charged in the investigation.
FBI agents raided government offices and the homes of County Commissioner Jimmy Dimora and Auditor Frank Russo months ago.
Neither have been charged and both deny wrongdoing.
WKYC-TV/The Associated Press