2014–2015: Debut and career beginnings In December 2014, Kihyun competed in the
Mnet's survival show
No.Mercy. Along with six other trainees from the show, Monsta X was formed, a hip-hop idol group that debuted under
Starship Entertainment, with the EP
Trespass on May 14, 2015. In 2015, through the survival show, he had been featured in two of its soundtracks, for "Pillow" with
Sistar's
Soyou and
Giriboy on January 14, and "0 (Young)" with Giriboy,
Mad Clown,
Jooyoung, and other remaining trainees in
No.Mercy on February 4. In May 2015, Kihyun and fellow
Monsta X member
Jooheon, released an original soundtrack "Attractive Woman" for
KBS2's
Orange Marmalade. In October, he released his first solo original soundtrack "One More Step" for the
MBC's television drama
She Was Pretty. In April, Kihyun became an MC for
MBC Dramanet's
Tasteful Beauty Plus. He participated with
Son Tae-young and
Kim Ji-min, as one of the beauty information and tips experts. Kihyun sung the acoustic version of "The Tiger Moth" for the soundtrack for
MBC's drama
Shopping King Louie, which was released on October 27. In June 2017, an original soundtrack titled "I've Got A Feeling" for
SBS' drama
Suspicious Partner was released. In May 2018, Kihyun recorded "Can't Breathe" for MBC's
Partners for Justice with fellow Monsta X member Jooheon, and in June, he also recorded "Love Virus" for
tvN's drama ''
What's Wrong with Secretary Kim'' together with
WJSN's
Seola. For Monsta X's album
All About Luv, Kihyun participated in writing and producing of three songs, including "
Who Do U Love?" featuring
French Montana (and its remix by
will.i.am), "Middle of the Night", and "Beside U". He had previously co-written "I Do Love U" from
Take.1 Are You There? with three other members, as well as co-written and produced the song "No Exit" for their debut EP
Trespass. In April 2020, Kihyun released a song for the soundtrack of
KBS2's
Welcome, titled "Again Spring",
2021–present: Solo debut with Voyager and other solo activities In February, Kihyun released a song for the soundtrack of the drama
Replay: The Moment, titled "O.M.O.M.". He was praised for his work in the drama, particularly his voice was able to express the "sweetness and softness" that complemented the drama. In August, Kihyun appeared as a special guest on
Naver Now's
Night Studio, where he sang covers of several songs, including "Middle of the Night" by Monsta X and "Radioactive" by
Imagine Dragons, with a live band. He also became a new DJ for Naver Now's
Midnight Idol, alongside group member
I.M. He made his solo debut with the single album
Voyager, along with the lead single of the same name, contributing to the lyrics of the song ", (Comma)" on March 15, 2022. Kihyun tested positive for
COVID-19 on March 30. On August 4, Kihyun released a song for the soundtrack of the
webcomic After School Lessons for Unripe Apples, titled "Is This Love". On September 16, he appeared and performed in the music festival KPOP LAND 2022, to commemorate love, peace, and a better world, in
Jakarta, Indonesia. On October 14, Kihyun performed in the
KCON 2022 Japan, held at
Ariake Arena in
Tokyo. On October 24, he released his first
EP Youth, along with the lead single of the same name. On October 25, Kihyun was selected as the sole host for Naver Now's new live show
PLAY!, starting on November 7. On November 12, he released a song for the soundtrack of the new SBS' Friday-Saturday drama
The First Responders, titled "Fire". In January 2023, Kihyun had a pictorial and an interview for the fashion magazine
Arena Homme + Korea. In April, he became a fixed panelist for
JTBC's current affairs and liberal arts program ''Han Moon-cheol's Black Box Review''. On April 16, Kihyun and Joohoney participated in the soundtrack of
TVING's original
Our Game: LG Twins, titled "Awake". It is a song about overcoming difficulties by cheering each other on and raising hope, which combines rock and hip hop, and contains a moving theme of turning adversity upside down. They also participated in its pitch and theta for victory before the game series against
Doosan Bears. On May 7, he released a song for the soundtrack of the television series
Tale of the Nine Tailed 1938, titled "Full Moon". In June, he attended the 2023 Seen Festival in
Hội An, Vietnam. On June 22, Kihyun attended the Korea-Vietnam Cultural Exchange Night, held at
Vietnam National Convention Center, as "K-pop Representative Singer". It was a place to enjoy K-pop and
V-pop together, to strengthen cultural consensus between the two countries and promote friendship for the future generations. In March 2025, he held a free fan event after his military discharge. On May 25, Kihyun performed at the Peak Festival 2025, held at Nanji Hangang Park in Seoul. On June 28, he performed at the Someday Festival, in commemoration of its 10th anniversary, held at
KINTEX in
Ulsan. In October, it was announced that Kihyun will be one of the judges for the vocal survival show
Veiled Musician. == Personal life ==