In an essay written for Newsweek, the Legion actor claimed that he began using the narcotic as his career started to pick up in the 1980s as it was always readily available on film sets.
"It was very casual at first. That's what people were doing when they were at parties. Cocaine was even in the budgets of movies, thinly disguised," he explained. "It was petty cash, you know? It was supplied, basically, on movie sets because everyone was doing it. People would make deals. Instead of having a cocktail, you'd have a line.
"By the time I was doing The Big Easy in the late 1980s, I was a mess. I was getting an hour of sleep a night. I had a reputation for being a 'bad boy', which seemed like a good thing, but basically I just had my head stuck up my ass."
However, he insisted that the long road to sobriety taught him valuable lessons, including how to be humble about his life and success.
"That time in my life - those years in the '90s recovering - actually chiselled me into a person," he wrote.
"It gave me the resolve and a resilience to persevere in life. If I hadn't gone through that period, I don't know if I'd still be acting. In the end, it taught me humility. I really learned to appreciate what I have in this life."
Quaid recently spoke out in support of his troubled brother Randy.
He can be seen next in the upcoming comedy Playing The Field alongside Uma Thurman and Gerard Butler.