[1] He is known for starring as Saki Mizushima in The Idolmaster SideM, Niko in Nanbaka, Steve Kanamori in 100% Pascal-sensei, Subaru Hoshiyomi in Future Card Buddyfight Ace, Invisible Stalker/Perm Stripe in Egumi Legacy, and the titular main character of Kinokoinu: Mushroom Pup.
[3] He was later educated at Human Academy [ja] and 81 Actor's Studio, and he joined 81 Produce Junior on 1 April 2014.
[4][5] In January 2016, it was announced that Kobayashi would star as the cross-dressing male idol Saki Mizushima in The Idolmaster SideM, a sub-franchise of The Idolmaster franchise; he subsequently received praise for his androgynous voice (which he was already known for at the time), with Kusuri Yūki from Net Lab praising it as "a perfect casting".
[12] In December 2023, he was cast as Mitsuru Tenma in Ensemble Stars!, after the character's previous voice actor, Junya Ikeda, was arrested for bank account fraud.
[13] In 2024, he starred as Invisible Stalker/Perm Stripe in Egumi Legacy and the titular main character of Kinokoinu: Mushroom Pup.