Mel is said to have been the son of Conis and his wife, Darerca, the sister of Saint Patrick. Mel accompanied his uncle to Ireland and helped to evangelize in that country. According to the Life of Saint Brigid, Mel is said to have had no fixed diocese, which might be explained by his being a missionary. Saint Patrick himself built the church at Ardagh and to this he appointed his nephew, Mel. The cathedral at Ardagh is dedicated to Saint Mel. Acting upon the counsel of St. Paul, Mel supported himself by working with his hands, and what he gained beyond bare necessities, he gave to the poor.

For some time Mel lived with his aunt Lupait, but slanderous tongues spread serious accusations against them. Saint Patrick himself came to investigate their conduct. Mel was plowing when he arrived, but he cleared himself of the charge by miraculously picking up a live fish from the ground as if from a net. St. Patrick was satisfied, but he told his nephew that, in the future, he was to do his fishing in the water and his plowing on the land. Moreover, he enjoined Mel and Lupait to avoid scandal by separating, living and praying far apart.

Saint Mel's feast day is February 6.