He is best known for his 14-year tenure with Pro Wrestling Noah. During his time in Pro Wrestling Noah, Kobayashi is a former one-time GHC Heavyweight Champion, three-time GHC Junior Heavyweight and one-time GHC Tag Team Champion. He also won the 2012 Global League and the 2013 Global Tag League tournaments. He was also one half of the GHC Junior Heavyweight Tag Team Champions twice; his first reign was the inaugural reign with his longtime tag partner and rival, Naomichi Marufuji, which saw the two hold the title for almost two years. His second reign was with his protégé, Taiji Ishimori. He first wrestled under his real name, but because of potential confusion with his mentor, Kenta Kobashi (in both English and Japanese), he decided to drop his surname and only use his given name. He also spells his ring name with Roman letters in all capitals.