Kim Sung-kyu

Kim Sung-kyu was born on April 28, 1989 in Jeonju, South Korea. He attended Jeonju National University High School and was in the school rock band called "Coma Beat". When Kim first told his parents about his dream to become a singer, they rejected it because they wanted him to have a normal life and told him they'd rather he leave the house instead. He continued to practice in secret and came to Seoul alone to pursue his dreams after graduating from high school.

In 2007, he auditioned for SM Entertainment but failed to make the cut, and auditioned once more in 2008 only to fail again. Due to his admiration for rock band Nell, he initially auditioned at Woollim Entertainment under the recommendation of Nell's manager whom he'd met coincidentally at the café where he worked at part-time. With a hurting stomach, Kim went to his audition and lightly threatened them by saying, "If you don't pick me, you're going to regret it." Afterwards he rushed to the hospital immediately and got an appendectomy. On the day of his release, he received the notification that he had passed his audition. Originally intending to pursue rock music in a band, Kim instead became a trainee for the dance group Infinite, of which he would later assume the positions of leader and main vocalist. Despite being criticized by his school friends, he believed that it was an opportunity nonetheless and persisted. In 2010, Kim finally made his debut with Infinite on June 9.

On February 15, 2013 SKim graduated from Daekyung University's Practical Music program and received along with members L, Sungyeol, Hoya, and Dongwoo, the 'Proud Daekyung University Student Award' in hopes that the group would continue to grow and bring prestige to the school. The members had been accepted through a special screened admittance in early 2011. Kim was a student of Practical Music at Hoseo University.