Born in 634 in Chihara, Katsuragi, Yamato Province, his secular name was En no Ozunu. From childhood he devoted himself to mountain asceticism, opening sacred mountains across the Kii Peninsula including Katsuragi, Ōmine, and Kumano. Legend credits him with supernatural powers and command over two demon servants, Zenki and Goki. In 699 he was exiled to Izu Ōshima on false charges, yet reportedly walked across the sea to climb Mt. Fuji during exile. In 701 he was pardoned and is said to have ascended to heaven at Tenjōgatake in Minoo. Recorded in the official chronicle Shoku Nihongi, he is considered historical, though most of his life is shrouded in legend.

A superhuman ascetic roaming the mountains. Unbowed before authority and merged with nature's spiritual power, he became the ideal for all later Shugendō practitioners.

Revered as the founder of Shugendō at sacred mountains nationwide, the tradition centered on Ōmine and Katsuragi continues today. The thirty-six-site pilgrimage of En no Gyōja sacred sites endures, and in 1799 Emperor Kōkaku bestowed the title "Jinpen Daibosatsu."