Hyungwon joined the Mnet reality survival program No.Mercy in 2014, which led him to become part of the hip-hop boy group Monsta X. The six-member group debuted in May 2015 with the EP Trespass. In 2017, they released their first studio album titled The Clan Pt. 2.5: The Final Chapter. That same year, Hyungwon landed his first acting role in the rom-com Please Find Her, which aired on KBS2. He also started activities as a disc jockey under the stage name DJ H.ONE. In 2021, he starred as the male lead in Kakao TV’s teen musical drama Fly Again, where he also contributed to the soundtrack with the song Picture. In 2023, he and his fellow Monsta X member Shownu were launched as the group’s first sub-unit called Shownu X Hyungwon.