Park Kyung started his rapping career by promoting underground along with Zico. He used the name Holke, which means Horse-K. Park Kyung debuted in 2009 with the digital single "The Letter" as duo with Zico.
2015: ''Problematic Men'' and "Ordinary Love"
On August 27, 2015, the television variety show Problematic Men announced that Park Kyung would join the show as a regular cast member, starting September 6. A teaser image for Park Kyung's solo debut was released on September 9, 2015. His agency Seven Seasons commented, "Park Kyung displayed special affection and passion while writing and composing his solo song. This will be an opportunity for him to grow as an artist." "Ordinary Love" was produced by Korean/American jazz hip-hop producer Kero One alongside Park Kyung featuring Park Boram on September 21, 2015. The single topped multiple Korean real-time charts the day of its release and went on to debut at no.1 on Melon as well as no.3 on the Gaon Weekly Digital Chart.
2016: "Inferiority Complex" and "Ogeul Ogeul"
On May 18, 2016 at midnight KST, a teaser video was uploaded for Park Kyung's upcoming single "Inferiority Complex" feature GFriend's Eunha, with the full video and the song being released seven days later. In addition to releasing a song together, in May Park Kyung and Eunha starred in the second season of the online showOh My God! Tip, in which they act out tips for handling difficult situations. On May 25 at midnight KST, Park Kyung released the music video for his single "Inferiority Complex". It's a cute and romantic duet that features GFriend's Eunha, and in the music video the two singers play a couple with a bit of a jealously issue. The video includes fun scenes of them on a home shopping channel and their own version of the live broadcast show My Little Television, and features plenty of cute scenes of the pair. The single was ranked no.1 on a variety of Korean real-time music charts. In October, Park Kyung appeared on the show Celebrity Bromance with fellow Problematic Men cast member Kim Ji-seok. On December 15, it was announced that Park Kyung would be releasing the single "Ogeul Ogeul" four days later. "Ogeul Ogeul" was first released as a mixtape song in 2013; the backing track is by Kero One. The title is a transcription of the Korean expression 오글 오글, which refers to the cringing feeling experienced when one is watching something cheesy.
2017: ''Notebook'' and "Yesterday"
On January 8, Block B announced that Park Kyung would be releasing his first mini-album, Notebook, on January 18. The album contained five songs, including three that had been previously released as singles. Park Kyung composed the song "Yesterday," which was released by Block B on February 6, 2017 as a digital single "Yesterday." The song achieved an "all kill," topping six of Korea's real-time music charts. He also produced the song, "Love or Not," which was released by fellow Block B member Taeil on June 12. The song featured Kim Se-jeong of Gugudan and was nominated for a 2017 Melon Music Awards Hot Trend Award. Two weeks later, "The Night Sky," a song from the drama The Best Shot was released; Park Kyung performed on and co-wrote the song. On July 31, the MBCtelevision network announced that Park Kyung would appear in a new variety show, Mystery Rank Show 1, 2, 3, which began broadcast August 4. The next day, Park Kyung released the digital single "Wiped" as part of an endorsement campaign. During the Chuseok holiday, Park Kyung appeared as a host for the annual international public diplomacy show Quiz on Korea, along with Leeteuk.
2018: "Don't Leave" and "Instant"
On January 8, 2018, Block B released the album Re: Montage with a lead single, "Don't Leave," written and produced by Park Kyung. In June 2018, Park Kyung announced a new single, "Instant," which was released June 22 and featured the singer Sumin. The song is in the alternative funk style, with lyrics about how modern technology has affected human relationships. In early July 2018, it was announced that Park Kyung was producing the upcoming single by the group The Boyz, expected to be released later in the month.
2019: "28.3°C"
On February 18, 2019, it was announced that Park Kyung would hold a solo fan meeting, titled "28.3°C," on March 9 and March 10 in Seoul. Tickets to the meeting sold out February 25. In April 2019, it was announced that Taeil and Park Kyung would hold two concerts in Seoul together on May 25 and 26. On November 24, 2019, Park Kyung published a tweet, which was later deleted, accusing six acts of engaging in "sajaegi," or chart manipulation, in which an artist buys or streams their own music in bulk in order to place higher on the music charts. The artists all denied manipulating the charts and announced their intentions to file legal actions against Park Kyung. The publicity surrounding the incident led several industry insiders to publicly state that sajaegi was increasingly impacting Korea's digital charts. On December 7 and 8, 2019, Park Kyung held a solo fan meeting, "28.12°C," in Seoul.
