|“||I'm in charge of rap and performance in MAMAMOO, sparkling Moonbyul!||”|
— Moonbyul's MWAVE greeting
Moonbyul's Career section excludes her activities with MAMAMOO.
On May 23, Moonbyul officially debuted as a soloist with the single Selfish, with the song being included in MAMAMOO's Red Moon EP. The song was a collaboration single with Seulgi. Moonbyul also became the first MAMAMOO member to officially make a solo debut.
Moonbyul released a collaboration single with Punch on February 4, titled Weird Day. On February 14, Moonbyul released her first EP titled Dark Side of the Moon, with the single Eclipse as its title track.
On May 29, Moonbyul released a reissue titled 門OON, with the single Absence as its title track; 門OON's Kihno version features all the songs in Dark Side of the Moon. Moonbyul held an online concert on VLive, titled "Moonbyul 1st Ontact Live '門OON'", on May 30.