Hardy appealed an initial guilty verdict from last summer and was set to go to trial again on Monday, but prosecutors decided to dismiss the case after the victim, Nicole Holder, did not appear at the county courthouse to testify.
According to court papers filed Monday, Holder never made herself available to the Mecklenburg County district attorney's office to prepare for trial and law enforcement officials were unable to locate her to serve a subpoena.
The prosecution also said it had reliable information that Holder had reached a civil settlement with Hardy.
District Attorney Andrew Murray said it could not adequately continue with a trial without live testimony from Holder.
According to the police report from the incident, Hardy assaulted Holder and threatened to kill her during an altercation in May 2014. Holder said Hardy choked her with both hands around her throat and threw her onto a couch covered with assault rifles and shotguns. She said Hardy told her all the weapons were loaded.
Hardy was initially convicted of two misdemeanors -- assault on a female and communicating threats.
The NFL allowed Hardy to be placed on the commissioner's exempt list in September after he played in Carolina's season opener and was deactivated by the team for the second game of the season.
Hardy, set to become a free agent next month, tied a Panthers record with 15 sacks in 2013. Carolina placed the franchise tag on him at a cost of $13.1 million for the 2014 season.
A sixth-round pick by the Panthers in 2010, Hardy has 34 sacks in 63 career games with Carolina.