Shintaro Tsuji is the founder of Sanrio Co., Ltd. Tsuji founded Sanrio, the Tokyo based character-branded merchandise company, in 1960. He has also served as producer for the anime movies Sanrio made from 1977 to 1985, and is also a storywriter. Some of his stories include Nutcracker Fantasy (Kurumiwari Ningyo aka The Nutcracker, his adaptation of E.T.A. Hoffmann's "The Nutcracker and the Mouse King"), The Sea Prince and the Fire Child (Sirius no Densetsu aka The Legend of Sirius), and A Journey Through Fairyland (Yosei Florence aka Florence the Fairy), all of which have been made into animated movies by Sanrio.

Tsuji has also created a few Sanrio characters himself, including the Little Twin Stars.