Kevin Mayer, the hard-nosed and unvarnished Disney executive who oversaw the successful launch of Disney+ but was passed over to replace Bob Iger as CEO earlier this year, has jumped ship for the upstart streaming service TikTok. It’s a blow for Disney and a massive get for the proliferating Gen Z social media platform. “TikTok is in a position of clear strength but needed a veteran media exec and streaming background to lead this next chapter of growth and regulatory challenges. Mayer’s vast Disney experience speaks for itself,” Wedbush analyst Dan Ives told TheWrap. “It was a coup to get Mayer, as he brings a strong reputation around running a digital media platform and navigating the challenges that come with it. I view him as a home-run hire at the right time.” On Monday, Mayer was tapped as CEO of TikTok and chief operating officer of TikTok’s Beijing-based parent company ByteDance after spending nearly 20 years at Disney, where he gained the reputation as a brilliant deal maker as well as a bit of a corporate bully. “This is without a doubt a loss for Disney,” Ross Gerber, CEO of media investment firm Gerber Kawasaki, said. “Can’t spin this in a positive way… it’s sad that they couldn’t work out the egos.” Mayer and TikTok did not respond to TheWrap’s request for comment. Mayer enters his new role during a critical time for TikTok. Not only is the short-video app trying to figure out how to monetize its huge user base, but it’s also contending with regulatory and security concerns. Last February, TikTok paid a record $5.7 million fine to the Federal Trade Commission after it “illegally collected personal information from children” after failing to obtain parental consent of users under the age of 13. And late last year, after the U.S. Army banned the use of the app among its soldiers, TikTok released its first “transparency report” amid criticism that the app is too closely tied to the Chinese government — China is also the app’s largest source of revenue. On Tuesday, Republican Missouri Senator Josh Hawley tweeted that he looked forward to calling Mayer in to testify in front of Congress. “TikTok tells The New York Times that it is not really a Chinese company because parent co. Bytedance is incorporated in Caymans. I got it. So TikTok and Bytedance are based in China, do business in USA — and seek tax shelter in Caymans,” Hawley wrote. “Sounds TOTALLY legit.” Ives said the tensions between China and the U.S. — which have only heightened during the current global health crisis — are a major obstacle for Mayer and TikTok, and should be a top priority for the new boss. “There is a need to make sure this does not further ratchet up, especially around privacy and censorship,” Ives said. On top of that, monetization is key if TikTok wants to avoid the same fate of Vine, a similar short-form video platform that exploded in popularity after its 2012 launch but struggled to generate revenues. Despite boasting 200 million active users in December 2015, Vine was discontinued by parent company Twitter less than a year later. TikTok faces similar challenges in converting its newfound popularity into revenues. “They hired him to turn TikTok into a business,” Gerber said. “Snapchat has been fumbling around for five years trying to figure out what it is, and right now TikTok is in the same boat. Snapchat doesn’t really make money; TikTok doesn’t really make money. The question is, ‘How do I monetize TikTok?’ If I’m Snapchat I would be very scared. They are fighting for the same users.” Last year, TikTok passed more than 740 million downloads, grossing roughly $177 million globally, according to research firm Sensor Tower. TikTok is privately held and doesn’t report on its revenue, but that figure would have been more than five times its 2018 revenue. But those numbers pale in comparison to Twitter’s $3.5 billion in revenue last year and the $70.7 billion at Instagram’s parent company Facebook. Unlike Facebook which has a deep well of user profile data, TikTok doesn’t collect as much personal information about its users, which means advertisers can’t target ads based on interests and demographics. That makes monetizing the platform difficult. TikTok, still in its infancy, has experimented with an ad-based model and an affiliate model. Mayer, who graduated with an MBA from Harvard Business School in 1990, was recruited to work at Disney in 1993 to spearhead Disney’s strategy and business development as it related to technology. From there, he moved up to executive vice president of Disney’s internet group, responsible for the operations, business plans, creative direction and distribution of Disney’s most popular web sites. After a brief stint running Playboy.com, Mayer rejoined Disney and played an integral role in the acquisition of Pixar in 2006 and then led the push to acquire Marvel, Lucasfilm and the Fox assets. Mayer has had an abundance of success at Disney, especially after the launch of Disney+ last November. His management style, however, has been criticized by former colleagues who have described Mayer as a “bulldozer,” a “screamer” and someone with a “bruising and belittling style.” “I wouldn’t be concerned about that,” Gerber said of the executive’s reputation for rough personal edges. “He’s been very successful, and I’d rather bet on a guy with that reputation. Where TikTok is, they need that operational acumen and the discipline that Kevin brings. [TikTok] is nothing more than a fad now. If he can’t turn this fad into a business, it’ll likely go the same way as Vine. Things can look really good when you don’t have to make any money.” Sean Burch contributed to this report.