TikTok Chief Executive Officer Kevin Mayer has left the company after just four months.
According to an internal memo sent out Wednesday, the 58-year-old blamed the 'changing political environment' for his abrupt departure.
Mayer's resignation comes three weeks after President Trump threatened to ban the video-sharing app in the United States, claiming it may be a national security threat.
TikTok - which boasts a whopping 689 million users worldwide - is owned by Chinese based ByteDance.
Under a law introduced in 2017 under President Xi Jinping, Chinese companies have an obligation to support and cooperate in China's national intelligence work.
Announcing his resignation, Mayer wrote in his memo: 'In recent weeks, as the political environment has sharply changed, I have done significant reflection on what the corporate structural changes will require, and what it means for the global role I signed up for.
'Against this backdrop, and as we expect to reach a resolution very soon, it is with a heavy heart that I wanted to let you all know that I have decided to leave the company.'
In an emailed statement, TikTok confirmed the departure and said that the political dynamics of the last few months had 'significantly changed' the scope of Mayer's role.
Mayer, who holds an MBA from Harvard University, previously spent more than a decade at Disney.
He most recently worked as the company's head of streaming, helping to make Disney Plus a runaway success.
Announcing that he had been poached by TikTok back in April, Mayer told The New York Times: 'I was happy with my job at Disney, [but] the magnitude of this opportunity was just something I couldn't pass up.'
However, Mayer's role suddenly became more complicated on August 6th, when President Trump signed an executive order threatening to ban TikTok if ByteDance did not sell the app's U.S. operations.
He has given them 90 days to do so.
Some security experts have theorized that the Chinese government may be able to obtain American users' data through the app, sparking fears among US politicians on both the left and the right.
Earlier this week, TikTok sued the Trump administration over the executive order.
'We do not take suing the government lightly,' TikTok said in a blog post penned on Monday.
'But with the Executive Order threatening to bring a ban on our U.S. operations ... we simply have no choice.'
Patrick Ryan, a technical program manager at TikTok, sued the Trump administration over concerns that he and his 1,500 colleagues, including many on employment visas, will lose their jobs next month if Trump' s order is enforced.
'These are not decisions that belong to the government,' Ryan said in an interview with Reuters.
'It's not okay to even consider.'
TikTok further claimed the proposed ban was simply 'a pretext for furthering the President's broader campaign of anti-China rhetoric in the run-up to the U.S. election."
ByteDance has been in talks to sell TikTok's North American, Australian and New Zealand operations to companies including Microsoft Corp and Oracle Corp.
Those assets could reportedly be worth between $25 billion to $30 billion.
Meanwhile, Mayer has not announced whether he is returning to Disney. His salary at TikTok is unclear.
He will be temporarily replaced by the company's General Manager Vanessa Pappas.
© Associated Newspapers Ltd.