Walt Disney agreed to buy George Lucas’s Lucasfilm Ltd. for $4.05 billion, pressing Chief Executive Officer Robert Iger’s $15 billion bet on creative franchises by adding “Star Wars” and “Indiana Jones.”

Lucas, 68, the sole owner, will get half in cash and the rest in stock, making him a major investor in the film, theme park and TV company, according to a statement yesterday from Burbank, California-based Disney. The first of a new trilogy of “Star Wars” films will be released in 2015, Disney said.

The deal furthers Iger’s pursuit of marquee content in an era marked by technology changes, such as $8-a-month video streaming and free game downloads, that disrupted Hollywood’s traditional revenue sources. Iger, who paid a combined $11.2 billion for Pixar and Marvel, said memorable characters will be valuable no matter what medium they appear in.

“Technology has proved more friend than foe to great storytelling,” Iger said in an interview. “It allows us to distribute in ways we never thought would have been imaginable.”

“The ‘Star Wars’ universe is immense,” McGowan said in an e-mail. “And the franchise has the potential be the biggest ever.”