Radcliffe, 21, is best known for his portrayal of the titular wizard in the Harry Potter film franchise. He is currently starring in the Broadway revival of the musical "How to Succeed in Business Without Really Trying."
"I became so reliant on [alcohol] to enjoy stuff," Radcliffe told GQ magazine. "There were a few years there when I was just so enamored with the idea of living some sort of famous person's lifestyle that really isn't suited to me. ... There's no shame in enjoying a quiet life. And that's been the realization of the past few years for me."
People.com said Radcliffe decided to stop drinking after he completed work last summer on "Harry Potter and the Deathly Hallows: Part 2," which is set to open July 15.
Radcliffe told GQ he declined to attend the movie's premiere party because he wanted to avoid the temptation of alcohol there. Instead, he said he watched "the Discovery Channel ... [with] a bowl of Sugar Puffs."
"As much as I would love to be a person that goes to parties and has a couple of drinks and has a nice time, that doesn't work for me. I'd just rather sit at home and read, or go out to dinner with someone, or talk to someone I love, or talk to somebody that makes me laugh," he told GQ.