Horn's appointment by Disney CEO Bob Iger comes on the heels of former Disney head Rich Ross' resignation after a series of flops including "John Carter."
Horn will take the reigns on June 11, and will be responsible for overseeing production, distribution and marketing of live-action and animated films from Disney and its units Pixar Animation Studios and Marvel, according to Variety.
“Alan not only has an incredible wealth of knowledge and experience in the business, he has a true appreciation of movie making as both an art and a business,” Robert "Bob" Iger, Disney’s chairman and chief executive, said in a statement, the New York Times reported.
In addition to his successes with the "Harry Potter" film series, Horn presided over movies including "The Dark Knight," "Charlie and the Chocolate Factory," "Happy Feet," "Sherlock Holmes," "The Departed," the second and third "Matrix" films and the Ocean’s trilogy, according to the Hollywood reporter.
Horn also served as executive producer of "The Hobbit: An Unexpected Journey."
Variety reported that Horn's appointment was "surprising" to many Disney employees, "given that many in the biz had expected Horn to bow out of the entertainment biz after ankling as president of Warner Bros," during which he often sparred with Time Warner Chief Executive Jeff Bewkes.
Horn is under pressure to revive Disney's movie studio, whose business suffered $84 million operating loss in the most recent quarter following weak box-office results for "John Carter," according to the Wall Street Journal.
Earlier this month, Walt Disney reported its second-quarter profits rose 21 percent, thanks in large part to revenue from the company's cable networks and theme parks, according to the Journal.