The son of Moon Hwee Tae who was a well known guitarist. Just like his father, TaeJo played the guitar and was considered a prodigy. At a young age, his family moved to Japan to help his father pursue a better career. After moving to Japan, TaeJo eventually gave up playing the guitar and became more rebellious. Instead of going to school he would get into fights, play at the arcade, steal, and spent his time around friends who weren't the best influence for him. Jaebum wanted to recruit him for JBL, so much that he flew all the way to Japan for him. If it wasn't for Jaebum, Taejo wouldn't of picked up the guitar again. In current chapters, Taejo is revealed to be the same age as Hwee Kang Kim (17) and both boys join JBL at the same time as trainees. They also attend the same school.