Born to a fishing family in Nakahama Village, Hata District, Tosa Province (present-day Tosashimizu City, Kochi Prefecture), he set out fishing in 1841 at the age of fourteen, was caught in a storm, and drifted with his companions to an uninhabited island (Torishima). After 143 days adrift they were rescued by the American whaling ship John Howland. Thanks to the kindness of Captain Whitfield, Manjiro went alone to Fairhaven, Massachusetts, and acquired English, mathematics, surveying, and navigation skills. After participating in the California Gold Rush (1849) to raise funds, he finally returned to Japan in 1851. In Bakumatsu Japan, people with fluency in English were extremely rare, and Manjiro played an important role as interpreter and information provider in the negotiations surrounding the opening of Japan around Perry's arrival in 1853. He also contributed indirectly to the conclusion of the Convention of Kanagawa (1854) and the Harris Treaty (1858). After the Meiji Restoration he taught English and navigation at the Kaisei School (one of the predecessors of what is now the Faculty of Engineering at the University of Tokyo) and contributed to Japan's modernization. He died on November 12, 1898, at seventy-one. His life—a dramatic transformation from fisherman to citizen of the world—continues to be told in many stories.

Possessed of an indomitable spirit that turned adversity into strength, and an abundant curiosity. The initiative of a fisherman's son who spread his wings across the world, and his sense of mission to become a bridge between Japan and the West, inspire many people.

As a pioneer who gave Japanese people their first authentic contact with American culture and the English language, he served as a bridge to the opening of Japan and its modernization. His life continues to be told as a symbol of Japan's internationalization, and the John Manjiro Commemoration Society is established in Tosashimizu City, Kochi Prefecture.