In a video posted on YouTube, Lucas said the decision to continue with the saga wasn't inconsistent with past statements.
"I always said I wasn't going to do any more and that's true, because I'm not going to do any more, but that doesn't mean I'm unwilling to turn it over to Kathy to do more," Lucas said.
He said he has given Kennedy his story lines and other ideas, "and I have complete confidence that she's going to take them and make great movies."
Kennedy added that she and Lucas had discussed ideas with a couple of writers about the future movies and said Lucas would continue to have a key advisory role. "My Yoda has to be there," she said.
In a statement, Iger said the acquisition is a great fit and will help preserve and grow the "Star Wars" franchise.
"The last 'Star Wars' movie release was 2005's 'Revenge of the Sith' — and we believe there's substantial pent-up demand," Iger said.
The deal brings Lucasfilm under the Disney banner with other brands including Pixar, Marvel, ESPN and ABC, all companies that Disney has acquired over the years. A former weatherman who rose through the ranks of ABC, Iger has orchestrated some of the company's biggest acquisitions, including the $7.4 billion purchase of animated movie studio Pixar in 2006 and the $4.2 billion acquisition of comic book giant Marvel in 2009.
Disney shares were not trading with stock markets closed due to the impact of Superstorm Sandy in New York.
AP Technology Writer Michael Liedtke in San Francisco contributed to this story.