if my friend was driving my car and got into an accident, who's insurance company is responsible for paying the damage

Please note that I am only licensed in New York and this is for informational purposes only.

I'm not sure about TN law, but in New York, both of your policies potentially could kick in. The owner's insurance would be primary, and the operator's policy would be secondary. If you do not have insurance, the coverage would "drop down" to the driver.

I hope this helps.

If you had coverage at the time, your insurance would pay first since he was using YOUR car with YOUR permission. If you don't have insurance, then his insurance would cover him for his possible negligence. It wouldn't cover you for your negligence (if for example he was a reckless driver and you knew it but let him drive anyway), nor would it cover the damage to your car unless it was due to the negligence of your friend.