The man once known as "America's Sheriff" was indicted in October 2007 on charges of conspiracy, mail fraud and witness tampering in a case that included allegations of pay-to-play schemes and money laundering. Prosecutors alleged Carona used the power of his office to help wealthy friends in exchange for campaign contributions.
Jurors acquitted Carona of all but the one witness tampering charge in January.
The appeal is based on the decision by prosecutors to secretly record a conversation between Carona and former Assistant Sheriff Don Haidl. Haidl cooperated with prosecutors in exchange for a plea deal.
Carona's defense attorney filed paperwork Wednesday to appeal his conviction on witness tampering. Carona hopes to remain free on bail pending his appeal.
The Associated Press contributed to this report.