Kang is a native of Busan. He aspired to be a musician since childhood but his parents had been against it. Instead, he focused on his studies and was admitted to Pusan National University on a scholarship, eventually graduating with a degree in chemical engineering.
After completing his mandatory military service and graduating from college, he worked for Lotte BP (now Lotte INEOS) in research and development. During his tenure at Lotte, he co-authored at least one chemical patent. He co-authored several research papers, as well.