He once worked as an assistant for his favorite author Takeshi Obata, and is influenced by Marvel comics such as the X-Men and Spider-Man.
When Watsuki was a young boy, his brother, who was three years older, drew manga. Watsuki’s older brother was his role model so he started drawing Manga as well. Watsuki was also inspired by a variety of early Manga artists such as Osamu Tezuka and Fujiko F. Fujio. Later on, his brother stopped drawing manga but, "Because Mr. Watsuki was dumb, he kept drawing it (manga) for a while.”
When Watsuki was in middle school, he practiced kendo. He still drew manga but also enjoyed sports. Watsuki admits that he was “so weak, in fact, that I was an embarrassment to my 183 centimeters of height." Watsuki never won a kendo match. He was once chosen to be a starter after a teammate was suspended for causing an uproar. Watsuki grew frustrated with kendo, and eventually quit. When he was challenged to come up with a new character for Rurouni Kenshin, he used his outlook on kendo to design Yahiko Myōjin. In high school, he won the Hop Step award for his work on the series Podmark. Not much is known about Podmark because it has not been translated to English.
When not working on manga, Watsuki enjoys playing video games, reading other manga, and watching television. His favorite American comic series is X-Men because he likes the action. His favorite anime (other than his own) is Neon Genesis Evangelion. He likes video games like Samurai Spirits, and action movies like Die Hard and The Matrix.
In November 2017, Tokyo Police raided Watsuki's home as part of an investigation into the purchase of child pornography. The search uncovered DVDs containing videos of naked girls less than 18 years of age. The serialization of Rurouni Kenshin: The Hokkaido Arc was put on hiatus after the details of Watsuki's charges were made public. In February 2018, Watsuki was fined ¥200,000. The Hokkaido Arc resumed serialization in June 2018.
