Maruyama Ōkyo (1733-1795) is a famous Shasei (Sketching) school painter of the Edo Era. Shasei requires the painter to observe the object depicted in person. During the Meiji period, especially after the promulgation of the Imperial Rescript on Education in 1890, which reinforced traditional Confucian moral values, Shasei was seen as a symbol of diligence and seriousness; Maruyama, as the patriarch of the Shasei school, was immediately included in many civilian books advocating traditional moral values, and became a representative model of diligence for children and young readers. Maruyama made his debut in the subject Shūshin (moral education) in primary schools, and was a tool for the official propagation of morality until the end of the Pacific War. Using a documentary approach, this paper examines how Maruyama and his stories of painting were depicted, reworked, interpreted and misinterpreted in various civilian and official documents from the Edo period through to the Meiji, Taisho and Showa periods. The paper also considers how teachers taught Maruyama in primary schools, enlisting a painter of the Edo period in the political mobilization of the state from the Meiji period onwards.