"It got a lot worse when I moved back to Brisbane and played for the Broncos."
Folau debuted as a 17-year-old winger for the Storm, won a premiership and represented Queensland and Australia early on in his career. But while things looked rosy from the outside, away from the cameras, his life was spiralling out of control.
"It got really bad," Folau said. "I just got caught up in the alcohol, women and all that sort of stuff.
"I was almost like a different person.
"I just knew I was drifting away from the person I really was and in the end those things were too enticing for me to resist."
Folau was raised as a Mormon but admitted he didn't really embrace religion until he suffered a serious ankle injury in 2011. At around that time he made the huge decision to change codes, signing for AFL club the GWS Giants.
He played only 13 games for the Giants, with many viewing his signing as a marketing gimmick for the AFL's newest club rather than a reflection on his ability with the Sherrin.
Despite his lack of on-field success, Folau said his time in Sydney helped change his life for the better.
"The years I spent playing AFL were the best two years of my life in that it changed my life around," he said.
"I look at those two years as a huge blessing because it changed my mindset, it changed my perspective on the way I play sport, the way I look at life. Just my relationship with people - my teammates, my family, my partner everything.
"I don't really know how to explain it, it's just a peaceful feeling inside."
Now firmly entrenched in rugby union as a pivotal member of the Wallabies, Folau is under contract with the NSW Waratahs until 2018.