The Lost star had been accused of repeatedly striking a female party bus driver outside an Ohio bar. The woman, Heather Bormann, later filed assault charges.
Bormann's attorney told Entertainment Weekly that he dropped the case in April after his client "intentionally failed and refused to provide full and timely co-operation and information".
Additionally, she apparently neglected to pay his out-of-pocket expenses after promising to do so.
It was previously reported that Fox faced no charges from the incident, though the case was not withdrawn until last month.
The news comes on the heels of Fox's Lost co-star Dominic Monaghan's allegations that Fox "beats women".