Tad Cummins pleaded guilty Thursday to obstruction of justice and crossing state lines to have sex with a minor.
Last week, his lawyer filed a document in a federal court in Nashville saying Cummins wanted to change his previous not guilty plea.
The 51-year-old Cummins disappeared with the girl last March. The two were found in April at a remote forest cabin near Cecilville, California, following a tip to police.
He is charged with transporting a minor across state lines for the purpose of engaging in criminal sexual conduct and obstruction of justice.