The actor went to the festival to unveil the comedy, which he wrote, directed and stars in as a porn-obsessed womanizer who tries to start a meaningful relationship with Scarlett Johansson's character.
Don Jon's Addiction was a huge hit with audiences and sparked a bidding war with studio heads, and on Monday it was picked up by Relativity Media.
Gordon-Levitt announced the deal in a video posted online, telling fans, "I'm here at Sundance and the good news is the movie that I wrote and directed, Don Jon's Addiction, just closed a deal, a really great big deal for it to come out all over the country and all over the world.
"I couldn't be happier. It's what I always wanted for this movie. I always intended for it to be for a big popular, mass audience. That's what's gonna happen, it looks like."