The Two and a Half Men actress said that she related to the role of Julie Speer in the film, and particularly the character's more troubled side.
"It doesn't feel like a crazy departure for me, mostly because in my personal life I'm able to experience all of those emotions. But I think every actress or actor thinks they have an untapped range, like a range their audience isn't familiar with," Greer explained to New York Mag.
"And that's not the first time I've done something really dramatic; it's just the first time that it's been recognised. I've been looking for the last couple years to get out of the quirky sidekick role.
"For some time I thought the next step would be getting the lead, to be the girl with the best friend. So, if that doesn't happen, I have so much fun doing these parts."
Greer also discussed getting to kiss George Clooney in The Descendants, admitting that she wondered if the multiple shots the scene took was one of his infamous pranks.
"It's fun to kiss George Clooney! We had this crazy sex scene in Three Kings a hundred years ago, but we never kissed in that; it was just sex. Alexander [Payne, the director] is so concise and knows what he wants, so he usually gets it pretty quickly," she recalled.
"But the kiss scene we shot more than two dozen times, from this angle, and this angle, and this angle. George is famous for doing practical jokes, and eventually I was like, 'F**k! Is George playing a trick on me? Is this a joke? At some point is everyone going to be like, Ah! We're just kidding!""
> Judy Greer engaged to Dean Johnsen
Watch the trailer for The Descendants below: