An attorney for Tad Cummins filed a notice of appeal on Wednesday, a week after Cummins was sentenced in federal court in Nashville for transporting a minor across state lines for sex and obstructing justice.
The girl's disappearance in March 2017 set off a national manhunt that ended when she was recovered in California more than five weeks later.
Prosecutors had asked for a 30-year sentence. The 52-year-old Cummins argued that was the equivalent of life in prison. He asked for the minimum sentence of 10 years.
In splitting the difference, the judge said Cummins committed a "pretty despicable crime" but also had no criminal record and was unlikely to reoffend.