The Academy of Motion Picture Arts and Sciences voted unanimously more than a week ago to make the voting members "significantly" more diverse, with the goal to double the number of women and diverse members by 2020.
The Oscar winner told ABC News that the changes won't have an impact "initially and not for a period of time."
"The Academy isn't the issue," he told ABC News. "The Academy is at the very tip of the spear at the very end. The real problems are the diversity from the beginning, the people who are greenlighting films."
Clooney, 54, explained that Hollywood studios need to change their approach to filmmaking.
"When I take a script to a studio and they give me five names that they'll make the film with, we want to change who all those people and those names are on that script," he said. "And that means diversity from the agencies, from the writers, from a lot of that."
Still, the "Hail, Ceasar!" star, whose new movie hits theaters Feb.5, considers the Academy's decision "a very good idea, and a smart thing to do."