Jiun Onkō born in Kawakita Matasuke’s house in the Takamatsu domain warehouse. At the age of 13, he was ordained at Horakuji Temple in Settsu, where he studied esoteric Buddhism and Sanskrit under its abbot, Sadaki Oshinami.
In 1744 (Enkyo 1), he rebuilt Choei-ji Temple in Kawachi and became its abbot. He gave his first lecture on the Buddhist precepts, and continued his practice and lectures at Koyasan and other places in the Kinki region.
In 1758, he retired to a hermitage called Shuoryu-an in the Ikoma Mountains to devote himself to research, and wrote a major work on Sanskrit, “Bokugaku Tsunryo.
With the support of Yanagisawa Yasumitsu, lord of the Yamatokoriyama domain, he built the hall of Kokyoji Temple and designated this temple as the head temple of Shōhō.
In his later years, he advocated his own theory of Shintoism, which he called Kumoden Shinto or Katsuragi Shinto.
In 1804, he ended his life at Amida Temple in Kyoto, and his body was brought to Kokyoji Temple for burial.