Greg Hardy says he's a changed man -- telling TMZ Sports he's got a new attitude and a new perspective after dedicating his life to mixed martial arts.
You already know Greg's backstory ... the NFL star was accused of domestic violence against a woman back in 2014 and initially convicted. The conviction was overturned in 2015.
He was also arrested for cocaine possession in 2016.
Hardy was essentially blackballed from the NFL ... so he ultimately decided to train in MMA.
We're told he made a real effort to clean up his lifestyle and focus on the sport -- and so far, he's been incredibly successful in his new career .