Kim Hyo-jung, professionally known as HYOLYN (효린), was born on December 11, 1990, in Incheon, South Korea. She gained recognition as the leader, main vocalist, and dancer of the South Korean girl group Sistar, which debuted in 2010 under Starship Entertainment. Hyolyn also led Sistar's sub-unit Sistar19. After the disbandment of Sistar in 2017, Hyolyn left Starship and established her own label, Bridge Entertainment, to pursue her solo career.

Hyolyn trained with JYP Entertainment before joining Starship Entertainment in 2010, just in time for the formation of Sistar. With her bandmates, she remained a strong presence on the Korean, Japanese, and U.S. charts for much of the 2010s. On the side, she began to foster a solo career. Hyolyn began to feature on various artists’ tracks, including Simon D and Dynamic Duo. She made her acting debut in the 2012 drama Dream High 2, portraying a fictional idol in the girl group Hershe. She also contributed to the drama’s soundtrack, further establishing her versatility as both a singer and an actress.

In November 2013, Hyolyn debuted as a solo artist with her album Love & Hate, which featured the lead singles "One Way Love" and "Lonely." The album was well-received, and she became the second South Korean artist to contribute to a Disney production by recording the Korean version of "Let It Go" for the animated film Frozen. Her ballad "Good bye" that was recorded for the drama My Love From the Star topped music charts in South Korea upon release.

Balancing her duties in Sistar and subunit Sistar19, Hyolyn continued to release solo singles and collaborations. Her follow-up solo effort, the It’s Me EP, landed in the Korean Top 20 in 2016. After Sistar split up the next year, she got right back on the singles trajectory, reaching the Top Three with “Blue Moon” and breaking into the U.S. World singles Top Ten with 2018’s “Dally” and “See Sea.” She released the comeback single “To Do List” in February 2018, while also announcing her own label BRID3 (pronounced ‘bridge’).

In 2019, she joined producer Melanie Fontana for the electronic dance single “youknowbetter.” Weeks later, Hyolyn embarked on her first international solo tour, hitting cities across Europe and Asia. “Dally” and “See Sea” later resurfaced on her 2020 EP, Say My Name, which returned her to the Top 20.

“Hug Me Silently” (featuring Crucial Star) and “To Find a Reason” (featuring Mad Clown and Kim Seungmin) were among her stand-alone singles over the next couple years. In early 2022, she released the Jooyoung collaboration “Layin' Low,” the lead single from her third EP iCE, which followed mid-year.