[7] Shownu continued to participate in the idol industry, becoming the backup dancer of Lee Hyori and doing promotions with her, as well as appearing in the music videos for "Bad Girls" and "Going Crazy".

[10][11] After Shownu auditioned and joined Starship Entertainment, he became part of the project group Nu Boyz, alongside Monsta X members' Jooheon and Wonho, as well as #Gun.

[12] In December 2014, Shownu competed in Mnet's survival reality show No.Mercy and debuted in the hip-hop boy group Monsta X, alongside the other six contestants, in 2015.

[23] In January, he was selected to host the Korean-Japanese music show The Power of K, alongside Block B's U-Kwon and Momoland's Nancy, which was broadcast simultaneously in Korea and Japan.

[24] On October 26, Shownu collaborated with the British band PREP's lead single "Don't Look Back", for their forthcoming album, alongside Hwang So-yoon of Se So Neon.

[39] In 2020, prior to the release of Monsta X's eighth EP Fantasia X, he injured his back, and the group delayed their comeback by two weeks to allow Shownu time to heal properly from his injury.

[58][59] On May 4, Starship announced that he would be taking a hiatus from Monsta X and would not promote for their upcoming comeback due to health problems related to his eye retinal detachment.

[62] In June, Shownu was announced to join as a judge on Mnet's dance competition show Street Woman Fighter 2, starting on August 22.

[66] On June 29, he appeared at the pop-up opening event of TAG Heuer's "Iconic Collection Carrera", with Hyungwon, in commemoration of its 60th anniversary, held in Gangnam-gu, Seoul.

[71] On September 8, he attended the launch event of Canada Goose's "Live in the Open" F/W collection, in collaboration with Rok Hwang and Matt McCormick, held in Seongdong-gu, Seoul.

[72] On September 14, Shownu attended the launch event of Calvin Klein's capsule collection, in collaboration with Son Heung-min, held in Yeongdeungpo-gu, Seoul.

[73] The brand hosted its Fall 2023 Calvin Klein Jeans' collection event, celebrating fashion and music, where he also attended on October 19, held in Tokyo.

[82] On February 28, he attended the launch event of MAC Cosmetics' MACximal Silky Matte Lipstick pop-up store, held at Lotte World Atrium Square in Songpa-gu, Seoul.

[84] In July, he appeared on KBS2's reality competition program Make Mate 1 as a surprise advisor of the team that performed Monsta X's "Love Killa".

[90] Shownu has cited singer and actor Rain, as well as international artists Michael Jackson, Chris Brown, and Bruno Mars as his role models.

[99] After his appearance for Fuerza Bruta Wayra in Seoul, its official SNS increased by 100%, with the number of followers reached almost two million, while it recorded more than 260,000 fresh viewers.

[103] In October 2018, Shownu and Monsta X member Wonho promoted the American sportswear brand Under Armour's shoe and clothing line through Dazed Korea.

[30] In August 2019, Shownu and Wonho promoted the American luxury fashion brand Tom Ford's latest perfume line through Elle Korea.

[106] In May 2023, Shownu promoted the Italian luxury fashion brand Dolce & Gabbana's classic shoe and clothing line, bags, and accessories through Vogue Korea.

[118] On November 24, Shownu participated in a charity event for the fashion magazine W Korea's breast cancer awareness campaign "Love Your W", held at the Four Seasons Hotel in Gwanghwamun, Seoul.

[119] Shownu participated as a reader of Edgar Allan Poe's Annabelle Lee and William Wordsworth's My Heart Leaps Up through the Naver's audio-only platform Audio Clip, alongside group member I.M, with the release of an interview video, a video of reading a book, audiobook recording site sketches, and a collection of NGs on Naver V Live Plus, to help the visually impaired people.