Shou Zi Chew is not a prolific TikToker. The 40-year-old CEO of the Chinese-owned app has just 23 posts and 17,000 followers to his name – paltry by his own platform’s standards.Chew’s profile sees him attending football games, visiting Paris and London, trying Nashville hot chicken, or boating on a lake, often with generic captions. (“Love the outdoors!”). Users have noticed: “Bro the TikTok ceo with 41 likes,” one person commented on his video of the outdoors. “Shout out to this small creator,” another wrote.Suffice to say, Chew is not an influencer. But his influence over one of the world’s fastest growing, most popular and – some say – most dangerous social networks is under increasing scrutiny.On Thursday Chew will appear before a US congressional committee, answering to lawmakers’ concerns over the Chinese government’s access to US user data, as well as TikTok’s impact on the mental health of its younger user base. The stakes are high, coming amid a crackdown on TikTok from the US to Europe. In the past few months alone, the US has banned TikTok on federal government devices, following similar moves by multiple states’ governments, and the Biden administration has threatened a national ban unless its Chinese-owned parent company, ByteDance, sells its shares.It’s one of the biggest tests yet for the Harvard business alumnus, who counts stints at the consumer electronics giant Xiaomi, Yuri Milner’s investment firm DST and Goldman Sachs on his resume, and has only been in the TikTok job since May 2021.Chew’s low-key online presence is reflective of his public profile. In the two years since becoming CEO, Chew remained relatively quiet even as TikTok was thrust into the spotlight. Save for select interviews he operates largely in the background, staying under the radar as the company promises regulators increased transparency. There’s a lot riding on Chew’s first congressional appearance, which might explain why, in recent months, he’s been on a publicity tour. In addition to various interviews, Chew has been quietly meeting with lawmakers as he gears up for his testimony before the House Energy and Commerce Committee.Chew has also worked to mobilize the platform’s US user base. In a video posted to the TikTok main account, Chew warned that “some politicians” could take the app away from “all 150 million of you” and asked people to share what they love about using the video-sharing service in the comments.Over the past year, the company has attempted to address some lawmakers’ concerns about both data security and teen mental health. TikTok says it spent more than $1.5bn on security efforts and started the process of deleting the US user data that was backed up to its storage centers in Virginia and Singapore after it started routing all US traffic through Oracle-owned servers in the US. The company also recently announced it was limiting screen time for its under-18 users to one hour.But it’s unclear how much he stands to change lawmakers’ minds, especially as bipartisan efforts to appear tough on China gain momentum, making it difficult for him to find allies in either party.Regulatory pressure growsBy the time Chew took over in May 2021, he had his work cut out for him. The now seven-year-old company had already gone through two CEOs in just one year – Kevin Mayer, who ran the company for three months, and Vanessa Pappas, who served as a temporary global head before Chew replaced her. TikTok was seeing explosive growth, boasting 150 million users just in the US, but also increased regulatory pressure over potential ties to the Chinese government.Though Chew has not formally worked at TikTok for very long, he has been involved with its parent company since its early days. Chew was an early investor in ByteDance, founded in 2012, before it began to develop short-form video apps, according to an interview with David Rubenstein, the founder of private investment firm and ByteDance investor the Carlyle Group.Chew, whose promotion to CEO landed him a spot on Fortune’s 40 under 40 list in 2021, joined the ranks of tech executives like Mark Zuckerberg and Elon Musk at a time when people in those roles, once the subject of unadulterated adoration and hero worship, had become the subject of ire and disillusionment.While his lack of public persona may have largely saved him from personal scrutiny, it could hinder his attempts at making inroads among lawmakers and members of the public who have become wary of Chinese surveillance.“The mystery of ByteDance and TikTok and the uncertainty around whether they are doing anything that’s unscrupulous is part of the problem,” said Matt Navarra, a social media consultant and founder of the industry newsletter and podcast Geekout. “So [Chew’s] lack of profile and lack of awareness of who he is may be a blessing, but also it might be a downfall given people want to understand TikTok and ByteDance to understand what the level of risk is.”Within months of joining, Chew started working to combat those concerns. In June 2021, Chew wrote a letter to lawmakers, reiterating the company’s commitment to transparency and emphasizing the company was run by him, “a Singaporean based in Singapore” and not China-based ByteDance.Nearly two years later, those conversations appear to have deteriorated, and even appeals to individual lawmakers have not assuaged fears.Senator Michael Bennet, a Democrat of Colorado who called on Apple and Google to remove TikTok from their app stores in February, met with Chew last month but said he was still worried about the national security risks of the app and the “poisonous influence of TikTok’s algorithms on teen mental health”.“Mr Chew and I had a frank conversation,” Bennet said in a statement. “But I remain fundamentally concerned that TikTok, as a Chinese-owned company, is subject to dictates from the Chinese Communist party and poses an unacceptable risk to US national security.”Into the hot seatIt’s not the first time US lawmakers have grilled TikTok, but it will be Chew’s first time in the hot seat. In September 2022, battling national security concerns over whether ByteDance may be giving the Chinese government access to US user data, TikTok’s chief operating officer Vanessa Pappas testified in front of the Senate Committee on Homeland Security and Governmental Affairs, contending there is no basis for concern and that TikTok is working to minimize how much data non-US employees can access.Chew, who once interned at Facebook, has echoed the same sentiment since he started at TikTok: the company is not beholden to the Chinese government. “TikTok has never shared … US user data with the Chinese government. Nor would TikTok honor such a request if one were ever made,” Chew will say on Thursday, according to written testimony posted ahead of the hearing.In the past, Chew has pointed out that while ByteDance is based in China, TikTok itself is not available for download in China and all US user data is stored in Virginia with a backup in Singapore.Though the US government has offered no evidence that the Chinese government has accessed user data from TikTok, their concerns about the security of consumer information in the hands of the company aren’t unfounded. ByteDance employees have reportedly accessed US user data, and the Department of Justice and the FBI have launched an investigation into allegations that some ByteDance employees had obtained TikTok user data to investigate the source of leaks to US journalists.Several civil liberties and privacy advocates argue banning TikTok would amount to censorship, and that concerns over data security would be best addressed through a federal privacy regulation that limits how much user data all tech companies can collect and share with government agencies and third parties. The argument appears to have fallen flat and industry experts appear skeptical there is much Chew could say to assuage lawmakers’ concerns.“It’ll be interesting to see how believable and authentic he comes across or how rehearsed those answers [to Congress] are,” Navarra said. “I think that TikTok has to come in and tell these lawmakers something they haven’t already heard. Because if they don’t then the likelihood of banning is certainly gonna increase.” More