In 2005 Hyoseong was a finalist in television channel Mnet’s “Battle Shinhwa” which led to her signing a recording contract with Good Entertainment. In 2007 she was going to debut in the group ‘Five Girls’, together with G.NA, Wonder Girls’ Yubin, After School’s Uee and former T-ara member and current Spica member Yang Jiwon, however, the group disbanded before they were able to debut due to the company’s financial problems. Hyoseong was later discovered by TS Entertainment through a show aired on SBS MTV, called “Diary of Five Girls”, and spent two years with the company as a trainee. In 2009 Hyoseong debuted with Song Jieun, Han Sunhwa, and Jung Hana as the four member girl group Secret.