Born in Tokyo in 1933. After graduating from the Tokyo Metropolitan Nihonbashi High School in 1952, Okamoto worked for 26 years as an art director at Toppan Printing Co., Ltd. During this time, he began to teach himself watercolor painting, and started submitting his work to the Japan Watercolor Exhibition and the Niki Exhibition. He held his first solo exhibition at Muramatsu Gallery in 1956 and also founded the “Seisaku Kaigi (Artist Conference)” that same year along with Yoshie Yoshida and others. An encounter with the Neo-Impressionist works of Georges Seurat inspired him to depict contemporary illness and malaise using bright, vivid colors and simple forms. In 1956, Okamoto exhibited at the Yomiuri Independent Exhibition. He received honorable mentions at the Shell Art Prize Exhibition in both 1962 and 1963, and the Grand Prix at the exhibition for the inaugural Nagaoka Contemporary Art Museum Prize in 1964. During this time, he exhibited a series of works including “Holy Scenery” and “Ten Indians” that conceal a sense of hollow emptiness beneath a humorous surface. Okamoto has shown his work at several museums both in Japan and abroad. He participated in the “Trends in Contemporary Art” exhibition held at the National Museum of Modern Art in Kyoto (1964), “15 Contemporary Japanese Artists” at the Kunsthaus Zurich (1965), and “The New Japanese Painting and Sculpture” at the Museum of Modern Art in New York (1966). In 1968, Okamoto visited the US at the invitation of the Japan Society, touring New York and other American cities as well as Europe. In 1969, he received the Frontier Prize at the “Contemporary Japanese Art” exhibition. Okamoto has also held numerous one-man shows, including “The World of Shinjiro Okamoto: 25 Years” at the Ikeda Museum of 20th Century Art (1979), “The World of Shinjiro Okamoto – Tokyo Shonen” at the Niigata City Art Museum (1988), “Shinjiro Okamoto - The Laughing Panorama Museum” at the Museum of Modern Art, Kamakura & Hayama (1998), “Shinjiro Okamoto – Laughing Snow, Moon and Flower (Roly-Poly Cherry Blossoms)” at the Ikeda Museum of 20th Century Art (2001), and “Shinjiro Okamoto’s Panoramic Humour Universe (The Philosophy of Humour 1950-2001)” at Tokyo Gallery + BTAP Beijing (2008). Okamoto is a well-known Japanese pioneer of Pop Art.