Song Hayoung (송하영) is the vice-captain, main vocalist, and main dancer of the girl group fromis_9 under Pledis Entertainment. Prior to her debut, Hayoung used to join hip-hop dance competitions. Hayoung appeared and competed in the show "Idol School" where she ranked 2nd place, earning a spot in the group fromis_9.
She debuted as a member of fromis_9 on January 24, 2018 with the mini album To. Heart.