Henjo was Kurodo (keeper of imperial archives) for the Emperor Ninmyo, who favored him, and reached the position of Jugoinojo Kurodo no to (Junior Fifth Rank, Upper Grade, head of Kurodo) in 849, but upon the death of the Emperor Ninmyo, he became a priest and was a disciple of Ennin and Enchin.
仁明天皇の蔵人で、849年（貞祥2年）従五位上蔵人頭となったが、寵遇を受けた仁明天皇の死去により出家し、円仁・円珍に師事。