A racketeering conspiracy charge included in the 22-count indictment against Ryan and a lobbyist friend carries a maximum sentence of 20 years in federal prison.
The jury deliberated for 10 days before revealing that it had reached its decision, ending the state's biggest political corruption trial in decades.
The decision came on the jury's second attempt to reach a verdict. Two alternates were brought in after the judge dismissed two jurors eight days into the original deliberations.
Ryan was convicted of racketeering conspiracy, mail fraud, obstructing the Internal Revenue Service, tax fraud and lying to FBI agents.
Businessman Larry Warner was convicted of racketeering conspiracy, mail fraud, attempted extortion, illegally structuring bank withdrawals and money laundering.