Zhang, 35, lives in Beijing, China.
Zhang was born in 1983 in China's Fujian province, according to the Bloomberg Billionaires Index. Zhang's parents worked as civil servants, Bloomberg reported.
His name is based on a Chinese proverb about "surprising everyone with a first attempt," according to the South China Morning Post.
He married his college sweetheart.
Zhang graduated from Nankai University in 2005, where he started off studying microelectronics before switching his major to software engineering, the South China Morning Post reported.
The couple does not have any children, according to the South China Morning Post.
Zhang's first job out of college was at a digital travel booking startup called Kuxun.
"I was one of first employees. And I was an ordinary engineer at the beginning, but in the second year, I was in charge of about 40 to 50 people responsible for back-end technology and other tasks related to products," Zhang told ByteDance employees, according to the South China Morning Post.
Zhang credits that job for teaching him sales skills that he later used to grow ByteDance.
"I remember that at the end of 2007, I went to meet the client with the sales director," Zhang said, according to the Post. "This experience let me know what sales are good sales. When I established Toutiao and recruited staff, these examples helped me a lot."
Zhang also worked at Microsoft before founding ByteDance, the South China Morning Post reported.
Zhang founded TikTok's parent company in 2012.
The company is now worth $75 billion, according to Pitchbook, making it the most valuable privately held company in the world.
The company owns several social networking apps that operate within China, Business Insider previously reported. The company released a WeChat rival called FlipChat, and a video-messaging app called Duoshan in 2019.
Zhang and ByteDance's first product was a news aggregator app called Toutiao.
Zhang wanted to create a news platform whose results were powered by artificial intelligence, separate from China's search engine Baidu, Business Insider's Paige Leskin previously reported.
"We push information, not by queries, by news recommendations," Zhang told Bloomberg in 2017.
Despite its focus on news, Zhang told Bloomberg's Lulu Yilun Chen and Mark Bergen in 2017 that ByteDance does not have any journalists on its staff like many other social networks.
"The most important thing is that we are not a news business," Zhang told Bloomberg. "We are more like a search business or a social media platform. We are doing very innovative work. We are not a copycat of a U.S. company, both in product and technology."
Zhang launched ByteDance's most successful app — TikTok — under the name 'Douyin' in September 2016.
TikTok is now the No. 1 non-gaming iOS app in the U.S, Business Insider reported in September. TikTok is one of the most popular social networks among American teens and has been downloaded more than 1 billion times.
TikTok still goes by the name 'Douyin' in China, Business Insider previously reported.
Zhang makes his own TikToks — and requires his senior employees to as well.
"For a very long time, I was merely watching TikTok videos without making any of them myself, because it's a product mainly for young people," Zhang said, according to the South China Morning Post. "But later on we made it compulsory for all management team members to make their own TikTok videos, and they must win a certain number of 'likes'. Otherwise, they have to do push-ups. It was a big step for me."
Zhang's leadership style is "soft-spoken yet charismatic, logical yet passionate, young yet wise," according to Time Magazine's Kai-Fu Lee.
TikTok's global reach makes Zhang's life "much more interesting."
Zhang wants the app to continue to grow abroad, saying that he hopes his ByteDance will be "as borderless as Google," according to the South China Morning Post.
"We must work harder, we must also be more perfectionist," Zhang said, according to the Post. "Just like there was an international division of labour in the industrial age, in today's information age there's also an international division of labour. Chinese entrepreneurs must also improve their own capabilities as they go global," he said.
However, TikTok's growing influence in the US has raised questions from US regulators.
TikTok agreed in February to pay a $5.7 million fine to the Federal Trade Commission over allegations the app illegally collected personal information from children under age 13 without parental consent, in violation of the Children's Online Privacy Protection Act, Business Insider previously reported.
The billionaire attributes his success to his work ethic.
Zhang learned the value of pursuing excellence while still in his first job at Kuxun, he told ByteDance employees, according to the South China Morning Post.
"At that time, I was responsible for the technology, but when the product had problems, and I would actively participate in the discussion of [the] product plan," Zhang said, according to the South China Morning Post. "A lot of people say this is not what I should be doing. But I want to say: your sense of responsibility and your desire to do things well, will drive you to do more things and to gain experience."
Zhang's fortune is growing rapidly: He made over $12 billion in 2018 alone.
The majority of Zhang's fortune comes from his 24% stake in ByteDance, according to Forbes.
Forbes first declared Zhang a billionaire in March 2018, estimating that Zhang was worth $4 billion. The magazine now estimates his net worth at $16.2 billion.
