Born in 1217 in Yamato Province, his courtesy name was Ryōkanbō. In 1245 he received precepts from Eison and inherited his master's spirit of "promoting dharma and benefiting all." In 1267 he went to Kamakura and based himself at Gokurakuji. Following the model of Shōtoku Taishi's Four Institutions, he established hospitals, dispensaries, and poorhouses, granting precepts to and caring for lepers and outcasts. He also undertook many civil engineering projects including roads and bridges, reportedly contributing to the repair of Waka-e Island harbor. He died in 1303 at age eighty-seven.

An activist Ritsu monk who put his master Eison's compassion into practice in Kamakura. His devotion to the sick and socially vulnerable was so thorough that he was described as "one whose compassion knows no bounds."

Gokurakuji remains a noted Kamakura temple and has been designated a Japan Heritage site. Ninshō's welfare work is regarded as the finest example of medieval Japanese charity, and his infrastructure projects — roads, bridges, and harbor improvements — significantly shaped Kamakura's built environment.