Gatou first met Kouichi Chigira, the director of Full Metal Panic's first season, by accident when he bumped into him in Shinjuku when he was late for work. The two were surprised to later meet each other at Gonzo's offices.
He has also worked as a scriptwriter on a handful of Kyoto Animation's shows after their involvement in adapting Full Metal Panic, most notably working as the lead writer on Hyouka. He also supervised the studio's production of Amagi Brilliant Park, which was adapted from another light novel of his.
In 2019, Gatou posted controversial remarks to his Twitter about teenage environmental activist Greta Thunberg, but later removed the tweet in response to public backlash and apologized for writing it.
