The actor explained that it was an acting challenge to bring humanity to Lawless's bootlegger Forrest Bondurant, who swings between childlike kindness and violently aggressive behaviour.
"I take characters as they come, characters that interest me, that have scope. And also, a diversity of different ranges and colours and characteristics that are interesting in finding paradoxes and dichotomies of man," Hardy said, reports Flicks and Bits.
Hardy continued: "[With Forrest, I was] like, 'How can somebody be so violent, yet at the same time be such a little boy?' Someone intrinsically innocent and naive and have such a heart, but then he'd do something on the other side that was so incredibly, horrifically horrible.
"And yet where the fulcrum is in the middle, someone that by the end of the film I want the audience to have the ability to care about that person."
The film's director John Hillcoat recently revealed that he was left "awestruck" by Hardy and also praised the actor's chemistry with co-star Shia LaBeouf.
Lawless will be released on August 29 in the US and September 7 in the UK. Watch a trailer below: