The 38-year-old added that he is also “not very social, preferring solitary activities like being online, reading, listening to music, and daydreaming about what may be possible”.
Zhang has also been under enormous pressure to convince the world that TikTok will not hand data over to China’s Communist Party, while also protecting his image at home by not appearing to give in to demands from the West.
News that he is stepping down comes as Beijing clamps down on the unprecedented influence of some of China’s biggest technology firms.
E-commerce giant Alibaba was fined 18.2 billion yuan ($2.78 billion) last month as part of a push by regulators to rein in dominant digital platforms.
As Alibaba’s problems mounted, its founder Jack Ma has been unusually absent from the spotlight after speculation that brash comments by him to regulators brought the hammer down on his firm.
Bytedance was among 34 tech companies summoned by regulators in April that were told to undergo “complete rectification” and “heed the warning” of Alibaba.
TikTok is believed to have around one billion users worldwide including more than 100 million in the United States.
While he was US president, Donald Trump made a series of demands on the Chinese company over security concerns, including calls for the US operations of TikTok be sold to an American company or it would be shut down.
The firm has insisted it would never provide user data to the Chinese government.
ByteDance now has more than 60,000 staff in 30 countries and last year Zhang said they were looking to recruit around 40,000 more.
The company also runs a series of popular products including Douyin—the Chinese version of TikTok—as well as news aggregation app Jinri Toutiao and productivity app Lark, which features cloud storage, chat and calender functions.