Born on February 26, 1911 (Meiji 44), in Futako, Tachibana District, Kanagawa (today Takatsu Ward, Kawasaki), as the eldest son of the manga artist Okamoto Ippei and the poet-novelist Okamoto Kanoko. After graduating from the regular department of Keio University in 1929, he went to Paris with his parents and spent eleven years there from age 18 to 30. While studying philosophy and ethnology at the Sorbonne, he joined the surrealist movement of André Breton and others, and later the secret society 'Acéphale' of Georges Bataille. With the outbreak of World War II in 1940 he left Paris and returned to Japan, and in 1942 was conscripted into the army, experiencing harsh military life on the Chinese mainland. After the war, in 1947, he showed 'Yakai' (Soirée) and became a member of the Nika-kai. In 1948 he published 'On Jomon Pottery,' discovering the innovativeness of primitive Japanese art. In 1951 he proposed 'polarism,' establishing his unique style of clashing oppositions on the canvas — black and white, good and evil, modern and primitive. As theme producer of the 1970 Osaka World Expo, he created the 'Tower of the Sun' (70 m high, with three faces — front, top, and back), which became the symbol of the expo grounds. The huge mural 'Myth of Tomorrow' (5.5 m × 30 m), painted in 1968 for Shibuya Station, was made in Mexico and then went missing; rediscovered in Mexico City in 2003, it has been on permanent display in Shibuya Mark City since 2008. In 1981 he became known for shouting 'Art is explosion!' in a Maxell television commercial. He died of acute respiratory failure at Keio University Hospital on January 7, 1996, aged 84.

A spirit of revolt that smashed common sense, tradition, and the fixed notions of beauty with all his might. With vehement words such as 'Art is explosion,' 'Art is sorcery,' and 'Create something outrageous,' he swept up the masses too. A rare being who combined sharp ethnological insight with a creative drive pure as a child's. He never married, and his secretary and adopted daughter Okamoto Toshiko (1926–2005) supported his late years as his public and private partner.

The greatest maverick and greatest star of postwar Japanese art. Representative works such as the 'Tower of the Sun' (Expo '70 Commemorative Park, with interior re-opened in 2018, an Important Cultural Property and Good Design Award), 'Myth of Tomorrow' (Shibuya Mark City), 'Chair That Refuses to Be Sat On,' and 'Painful Arm' — through cross-genre creation he made 'Taro' permeate all of Japan. 'Art is explosion!' is still a national catchphrase. The Taro Okamoto Museum of Art in Kawasaki and the Taro Okamoto Memorial Museum in Minami-Aoyama, Tokyo (his former studio), are the main facilities. The Taro Okamoto Prize (an open exhibition) has become the gateway for young artists.