Born in 1202 in Suruga Province (Shizuoka Prefecture), his formal name was Bennen. After studying Tendai, Shingon, and Zen, he went to Song China in 1241 and studied under Wuzhun Shifan at Jingshan. After returning, he became founding abbot of Jōtenji in Hakata at the invitation of the Song merchant Xie Guoming. In 1236, Kujō Michiie vowed to build a great temple rivaling Tōdaiji and Kōfukuji, inviting Enni as founding abbot of Tōfukuji (completed 1255). He reportedly brought back milling techniques from Song, transmitting methods for making udon, soba, and manjū. He also planted tea seeds in his mother's hometown in Shizuoka, originating Honzan tea. He died in 1280 and was posthumously titled "Shōichi Kokushi" by Emperor Hanazono.

An internationally minded Zen monk with broad learning spanning Zen, Tendai, and esoteric Buddhism, combined with the drive to actively introduce Song culture to Japan. Deeply connected with Hakata's merchant community, he served as a conduit for cultural transmission.

Tōfukuji flourished as the fourth-ranked temple of Kyoto's Five Mountains and remains the head temple of the Rinzai Tōfukuji school. At Jōtenji in Hakata stands a monument marking the birthplace of udon and soba; he is deeply revered locally as the one who brought udon, soba, manjū, and Hakata-ori textiles. He is also known as the father of Shizuoka tea.