He was a son of HATA no Michitake who was a feudal lord of Chita-gun in Owari Province. His name (良忍) is also written as 良仁 (Ryonin) and his bogo (priest title) was Koseibo or Kojobo. There exists a view that he was born in 1072.
He became a monk of Jogyozanmai-do Temple of Toto on Mt. Hiei and while engaging in zoyaku (odd jobs), he practiced Fudan Nenbutsu (chanting Nenbutsu throughout the day) under the guidance of Ryoga. He also succeeded Zennin and Kanzei at school of Endonkai (Perfect and Sudden Precepts) and strove for the restoration of Endonkai. When he was 22 or 23 years old, he entered a secluded life at Ohara in Kyoto and devoted to praying to Buddha but in the meantime, he founded Raigoin Temple (Sakyo-ku Ward, Kyoto City) and Jorengein Temple (some assert that Jakkoin Temple was also founded by Ryonin) and completed Ohara Shomyo (Buddhist liturgical chant) by unifying the divided Tendai Shomyo.
In 1117, he received the manifestation of Amida-Buddha and created Yuzu Nenbutsu based on the thought that Nenbutsu recited by oneself and others can be united with each other or 'Nenbutsu recited by a person can be nenbutsu for everybody,' and thereafter he advocated rebirth in Jodo (pure land) by means of Shomyo Nenbutsu (Invocation of the Buddha's Name) and made propagation at various places while carrying a meicho (name list) that was to be used for recording the names of people who made a connection with Buddha. According to the dream of Buddha's oracle that Ryonin had when he confined himself in Shitenno-ji Temple, he founded Shuraku-ji Temple at the residence of SAKANOUE no Hirono, then the feudal lord of Hirano-sho, Sumiyoshi-gun, Settsu Province (present Hirano-ku Ward, Osaka City), and it was the predecessor of Dainenbutsu-ji Temple, the head temple of the Yuzu Nenbutsu Sect.
In 1773, he was granted the shigo (posthumous name) of Shoo Daishi.