Director Shinobu Tagashira discovered Junji Ito's manga as a teenager through the horror magazine 'Halloween', and being deeply shocked by reading 'Tomie' and fascinated by the eeriness of 'Sōichi', she vaguely dreamed of one day directing an anime adaptation of Ito's work.

Tagashira kept voicing her wish to adapt Junji Ito's manga throughout her career, and in November 2016 she single-handedly launched the project that eventually became the first adaptation series, Junji Ito Collection, before returning to direct this second series.

Junji Ito Maniac is effectively a second season of the 2018 series Junji Ito Collection, sharing much of the same staff, including director Shinobu Tagashira, screenwriter Kaoru Sawada, and composer Yuki Hayashi.

To select the 20 stories to adapt, Tagashira wrote out the original titles on sticky notes, pinned them to a whiteboard, and spent hours staring at them while carefully weighing the episode order, the pairing of A and B segments, and the balance with the next-episode previews.

Tagashira personally drew the storyboards for every episode and built up each setting, scene layout, and situational detail herself to recreate the atmosphere of the original manga before handing all the prepared material over to each episode's staff.

The opening theme 'Paranoid' is performed by MADKID, with lyrics by LIN and YUKI and composition/arrangement by LIN, while the ending theme 'Iu Toori' is performed by Jyocho, written and composed by Daijiro Nakagawa.

Composer Yuki Hayashi's original soundtrack for the series, comprising 49 tracks, was released on August 2, 2023.

To celebrate the start of its Japanese television broadcast on July 7, 2024, the first episode included a special audio commentary track featuring cast members Takahiro Sakurai, Risa Shimizu, Ayaka Asai, and Tomoko Kaneda.

From January 24 to February 5, 2023, a collaboration event with Tokyo Tower was held, featuring exclusive merchandise sales and displays of original artwork, character designs, and storyboards from the anime.