[citation needed] In order to let their children understand their own culture and learn the language, the family decided to move back to Thailand and resided in the Bangkok suburbs where Nichkhun and his siblings attended local schools.

[citation needed] While still a trainee, Nichkhun was first introduced through JYP Entertainment's 2006 audition program SuperStar Survival in the episode filmed in Thailand.

[23] The following year, he made his debut in Thailand using his nickname "Khun", appearing as a backup dancer in a milk advertisement with Rain, who had become immensely popular in Southeast Asia due to Full House.

[26] In July, it was announced that he would be one of the panelists in the second season of popular talk show-cum-variety program Ya Shim Man Man alongside industry veterans Kang Ho-dong, singer-songwriter Yoon Jong-shin, talk show host Kim Je-dong and pop stars MC Mong, Seo In-young, and Jun Jin.

In 2010, along with Taecyeon and Yoon Eun-hye, Nichkhun played one of the main characters in a 12-minute music video drama for Cass Beer, which was released on February 8.

[32] In 2011, Nichkhun appeared in the music video of the single "Touch (觸動)" by Taiwanese Mandopop artist Will Pan, which premiered on January 31.

He also starred in the Japanese live-adaptation film of Ouran High School Host Club as Lawrence, the president of a Singaporean corporation.

In 2013, it was reported that he had been cast as a lead character in the Chinese television series One and a Half Summer, a role which required him to speak both Mandarin and English.

Nichkhun teamed up with CNBLUE's Jung Yong-hwa, B1A4's Baro, Infinite's L, and Winner's Mino for project group Lucky Boys (Super 5) for the 2014 SBS Gayo Daejun.

[44] In 2016, Nichkhun and actor Lee Jung-jin released a travel essay and photobook called '여행, 바람을 품은 지도' (Journey, Map that embraces the Wind) on May 3.

A special song called "Umbrella" dedicated to his fans was released in five different languages Japanese, Korean, Chinese, Thai, and English.

On May 22, 2020, his Thai romantic comedy My Bubble Tea began airing on Viu and starred Phiravich Attachitsataporn and Manasaporn Chanchalerm.

The Viu Original drama revolves around Manasaporn's character who concocts a special tea so that she can make her boss (played by Nichkhun) fall in love with her.

[75] On September 21, 2020, Nichkhun and Day6's Jae Park took on role as a member of crime-fighting boyband "4 2 Sing" in season three of Big Hero 6: The Series.

He then starred in the Viu Thailand original series Finding the Rainbow as one of the three protagonists alongside Sushar Manaying and Itthipat Thanit.

[81] Nichkhun starred in the Hollywood film The Modelizer, a romantic comedy directed by Keoni Waxman, alongside Byron Mann, Rayssa Bratillieri, Dominika Kachlik, and Kenneth Tsang.

He is often mentioned as a pioneer as his popularity in South Korea further contributed to the Korean Wave (Hallyu) in Thailand, which was still an emerging market for K-pop at the time of his debut.

[92][93][91] In 2012 he was awarded the Kerd of the Year, which recognizes the most popular and influential Thai celebrities chosen by host Woody Milintachinda and voted by the public.

[94] During his pre-debut appearances in SuperStar Survival and Hot Blooded Men, Nichkhun initially gained attention from viewers for his looks.

In an unprecedented move, he was cast as a panelist in the SBS talk show-cum-variety program Ya Shim Man Man 2 despite being a foreigner with a limited command of the Korean language and an idol trainee who had yet to debut;[27] after the first episode aired, he ranked first in the Naver online search rankings, with an opinion-editorial in The Hankyoreh noting that he "rose to stardom without saying a single word".

[108] His appearances on Our Neighborhood Arts and Physical Education in the badminton episodes alongside the likes of retired legends Lee Dong-soo and Ha Tae-kwon led Yonex Korea to appoint him as its brand ambassador in 2014, the first non-professional athlete to be chosen.