His birth name was either Kim Gyeong-myeong (金景明) or Jeon Gyeon-myeong (全見明), and his courtesy name was Hoe-yeon (晦然).

[1] He became a monk at the temple Muryangsa at the age of nine and passed the Seon national examination at 22.

When he was 78, King Chungnyeol offered him a position of rank and tried to make him National Preceptor, but Il-yeon declined.

The king again appointed him National Preceptor, and Il-yeon came down to the capital Kaesong (then Gaegyeong) but soon returned to the mountains on the pretext that his aged mother was sick.

Il-yeon is known as a prolific writer, and according to the inscription on his tombstone, he wrote around 80 volumes on Buddhist topics.