2017–2020: Early musical releases and Mirrors
In June 2017, Wang founded Team Wang for his solo activities in China and established a partnership with Snake or the Rabbit, a distribution company based in the United States; however, as he was still under JYPE, he couldn't promote nor release his solo music in South Korea and in Japan. In July he released his first self-written, self-composed solo song, "Generation 2". His first English-language single titled "Papillon" was released on 26 August and debuted at No. 1 on the Billboard China V Chart on the week of 16 September. On 30 August, he released "Novoland: The Castle in the Sky" (Chinese: 九州天空城), the theme song for iOS game Novoland: The Castle in the Sky 3D, breaking away from hip-hop and making a first try with melodious and classical music.
In September, Wang dropped out of Got7 activities in Japan due to health concerns and conflicting schedules. Throughout a year, he'd spend half of his time in China for his solo stuff, and half in Korea with the group. On 30 November, he released his second solo single, "Okay": similar to "Papillon", he wrote the lyrics, and composed and arranged the song together with Boytoy. In December, he was named the Breakthrough Singer of the Year at the Tencent Video Star Awards.On 20 April 2018, Wang released his third self-written single, "Dawn of Us", which speaks of appreciating the present and living with enthusiasm. His subsequent release "Fendiman", a collaboration with Fendi China, appeared at No. 1 on both the iTunes Singles chart and the iTunes Pop chart in the United States, making Wang the first Chinese solo artist to achieve that feat. In August 2018, he was awarded the Next Big Thing award at 2018 Teen Choice Awards. On 22 October, Wang signed with Canxing Culture to enter the international market; the following month, he released "Different Game", featuring Gucci Mane.
In March 2019, Wang performed a show titled "328 Journey Festival" at the Beijing Olympics Sports Center, selling out 5,000 tickets in 98 seconds. On 24 September, he released "Bullet to the Heart", the first single from his first album Mirrors. The song debuted at No. 1 on the Billboard China chart. The second single "Dway!" was published on 22 October. Mirrors, for which Wang supervised the whole process, and was personally involved in arrangements, lyrics writing, and music video shooting, was released on 25 October, reaching No. 32 on the Billboard 200 and becoming the highest-charting debut album for a Chinese artist in the history of the chart.
On 20 March 2020, Wang released the self-written single "100 Ways", mixing western and Chinese culture. It became the first song by a Chinese and K-pop solo artist to debut on Mediabase's U.S. Top 40 radio chart: it entered the chart in May, ranking 39th, and maintained its spot with a steady rise, ranking #24 on 19 July. On 7 July, Wang launched his fashion brand Team Wang Design, for which he served as the designer and creative director, after three years of development. On 4 September, he released the EDM single "Pretty Please", a collaboration with Swedish duo Galantis. He was behind the whole planning and editing of the music video, which paid homage to Hong Kong's love movies from the 90s, and directed it with Conglin. On 5 September, it was announced that Wang had invested in esports organization Victory Five. In December 2020, he released the Chinese-language single "Should've Let Go" with JJ Lin.
At the end of the year, Wang ranked 41st on Forbes China Celebrity 100 list.