[6] Prior to debut, No appeared in "2002 Survival Audition HeeJun vs. KangTa Battle of the Century" with bandmates Typhoon and Attack, as well as Kim Junsu, Super Junior's Sungmin and Eunhyuk.

No began pursuing an acting career in 2008 and gained notice with his supporting roles in the 2010 South Korean television series Pasta and My Girlfriend is a Nine-Tailed Fox.

His long-delayed television series Full House Take 2 (a loose sequel to the 2004 hit) secured air dates on Japan's TBS and Korean cable channel SBS Plus in 2012.

[9][10] No was cast as the male lead in the Chinese television series Love Expiration Date, for which he will also serve as OST music director, composing and writing songs for the soundtrack.

[15] In 2014, No appeared in a minor role in Roaring Currents (released July 30, 2014),[16] which became the highest-grossing film of all time in South Korea.

[18] In 2019, No played a lead role in the MBC television series Partners for Justice 2 as Jang Chul, a talented but mysterious ER doctor.

[19][20] On May 17, 2020, his newly formed band The Midnight Romance (stylized in all caps) released their self-titled debut single of the same name which consisted of three songs.