Some series he has directed include Garo: The Animation, Kakegurui, Dorohedoro, and Attack on Titan: The Final Season.
After graduating from high school, Hayashi did not have any specific career in mind to pursue.
[1] He later worked on his first series with in-between and key animation for Inuyasha in 2001.
[4] He was later offered by Masao Maruyama to direct Garo: The Animation at MAPPA, which he accepted.
[5] Shortly after completing work on Garo: The Animation, Hayashi was approached by MAPPA CEO Manabu Otsuka, to direct Kakegurui, to which Hayashi agreed.