Disney's Head of Streaming, Kevin Mayer, is set to become TikTok's chief executive, TikTok announced Monday.
Mayer will also serve as chief operating officer of ByteDance, the Chinese company that owns TikTok, effective June 1. Disney's stock fell nearly 1% in after-hours trading Monday following the announcement after closing the trading day up 7.15%.
It's a huge score for TikTok, a social media platform that hosts short form videos. Mayer was considered one of the top candidates to replace former Disney CEO Bob Iger, before Bob Chapek was ultimately named chief executive.
Mayer told CNBC's Julia Boorstin Monday the move has nothing to do with being passed over for the job, but because he saw this as a good opportunity.
"I enjoy my job, I admire Bob Chapek, and Disney's a fabulous company," he said. "When you have an opportunity like this you don't turn it down. I'm not getting any younger and it's such a good opportunity. But I love Disney and had no desire to leave."
Mayer is also leaving Disney after the successful launch of its streaming platform, Disney+, which rolled out in November and had 54.5 million subscribers as of May 4.
Mayer earned a reputation at Disney as being the company's top deal maker. He spearheaded the company's acquisition of BAMTech, which makes the streaming technology that powers the company's online video services.
He was also instrumental in Disney's acquisitions of Lucasfilm (and the Star Wars franchise), Pixar, Marvel and 21st Century Fox over the last decade and a half.
All of those properties have given Disney's content portfolio a huge boost, and resulted in several blockbuster films, helping Disney dominate the box office in recent years.
Disney veteran Rebecca Campbell will take over as Disney's head of streaming, the company announced in a news release. Campbell is a 23-year veteran of the Disney company and has held leadership roles across Disney's media, international and parks businesses. Most recently she served as president of Disneyland Resort.
"I wouldn't have left Disney if I didn't think it was in great hands," said Mayer. "Rebecca – I've known her for years -- she was a big part of the team as head of Europe for Disney+. She's wonderful and will do a great job. She's a great leader and she's going to pick up the reins and move forward seamlessly."
TikTok has been facing heightened scrutiny over its privacy and censorship of content in Asia, and U.S. politicians have raised national security concerns. Mayer told CNBC that he has experience with digital privacy and security at Disney, and is able to deal with privacy and data challenges facing TikTok.
"I know how to deal with those challenges and digital platforms almost universally face these challenges. At Disney we had privacy considerations we handled well," he said.
TikTok's parent company ByteDance is said to have a private valuation of about $78 billion.
--CNBC's Sarah Whitten contributed to this report.