He was born in Nagoya, Aichi Prefecture, Japan. Started drawing manga when he was in elementary school, and was influenced by OZAWA Satoru, MATSUMOTO Leiji and KAIZUKA Hiroshi. He graduated from Nagoya Institute of Technology. He released several hentai works on COMIC Penguin Club while working at a local automobile manufacturer. He went to Tokyo and became an assistant to KIKUCHI Shouta. Kitoh created the manga Shadow Star and Bokurano, both of which were adapted into anime series.

Kitoh's art and writing approaches are unique, with an instantly identifiable visual style and storylines that almost always lean towards the tragic spectrum and focus primarily on the vulnerability and cruelty of human beings. A recurring element throughout his works are graphic depictions of violence and sex involving children. However, his work is not categorized as lolicon and shotacon.

Characters he draws are almost always tall, skinny, and gangly for their ages and genders. His females, unlike those of most manga series, generally have small breasts and narrow hips. His males are rarely muscular, except under a few circumstances, usually extreme close-ups. Facial features are, usually, small and expressions subtle. Nudity is common in his works.