JB was born in Seoul, South Korea on January 6, 1994. He was scouted by JYP Entertainment from JYP Trainee Open Recruitment 5th Audition where he tied in first place with Jr. He then underwent training for 2 years and 6 months before his debut. Official statement made by JYP explained that a new group will be made during the second half of 2012, which includes Jr. and JB, rumored to be call J&J. The JJ Project debuted on May 20, 2012.
On February 3, 2012 it was revealed that JB and Jr. from “Dream High 2” will debut as boy band JJ Project sometime during the second half of 2012 through JYP Entertainment. Both became JYP trainees after they tied for first at the 5th JYP Open Auditions in 2009. Their recent appearances in “Dream High 2” have placed them in the media spotlight, allowing them to officially launch their singing activities.
On March 12, 2012 he released his OSTs for KBS's Dream High 2 "Together" with Jiyeon and "New Dreaming" with Park Seo Joon
On May 7, JYP Entertainment has revealed a teaser video for the 1st Single Album “Slot Machine”. On May 19 2012, the music video for "Bounce" was released and the duo debuted their promotions for "Bounce" on M! Countdown on May 24, 2012.
On March 11, 2013, it was announced that JB would be appearing as Seo Mi Joon on MBC's new drama When a Man Falls in Love. It was reported later that Jr. would also join the cast and will be playing the role of Ddol Yi, a part-time worker at Han Tae Sang (Song Seung Hun‘s character)’s mother’s store. This would be the second time both members of JJ Project was casted into the same drama since Dream High 2.