English: Most of the accounts of the life of St. Mel (Mael) emphasize his connection to other saints, especially the two patron saints of Ireland, Patrick and Brigid. It is not known exactly when or where Mel was born, but it is recorded that his father's name was Conis or Chonis and his mother's name was Darerca. St. Darerca was a sister of St. Patrick and was known as the "mother of saints" because all of her children (seventeen sons and two daughters) entered religious life, all were later recognized as saints, and all of her sons became bishops.

Mel and his brothers Melchu, Munis and Rioch accompanied their uncle Patrick to Ireland and helped him with his missionary work there. Mel and his brother Melchu were both reportedly consecrated bishop by Patrick himself. After St. Patrick built the church at Ardagh, he appointed Mel as Bishop of Ardagh, but according to the Life of St. Brigid, Mel is said to have had no fixed See for most of his life in ministry, which fits with other accounts of his being a traveling missionary and evangelist. Acting upon the apostolic precept, 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, and slanderous tongues spread serious accusations against them. St. Patrick himself came to investigate their conduct, but Mel and Lupait were cleared of the charges by supernatural means. When Patrick arrived, Mel was standing in a field plowing, but he reached into the dirt and picked a live fish out of the ground as easily as if he had lowered a net into the water. Lupait established her innocence by carrying glowing coals without burning herself or her clothing. Patrick was satisfied by this supernatural evidence, but he told his nephew in future to do his fishing in the water and his plowing on the land, and he also enjoined Mel and Lupait to avoid further scandal by living and praying far apart from one another.

According to ancient tradition, the most significant event in Mel's life is that he was the bishop who professed St. Brigid as a nun. During the rite, a mysterious manifestation of the Holy Spirit caused him to inadvertently read over her the episcopal consecration, about which St. Maccaille protested. Mel, however, was convinced that it happened according to the will of God and insisted that the consecration should stand. Mel proclaimed that Brigid alone of the abbesses of Kildare would be a bishop, and her successors, while not being bishops themselves, would continue to have a bishop's jurisdictional authority. This authority was respected for many centuries, and the other Irish bishops customarily sat at the feet of Brigid's successors until the Synod of Kells ended this custom in 1152.

There is a lot of confusing and conflicting evidence about the life of St. Mel, including the possibility that he and Melchu were the same person. Mel has a strong cultus at Longford, where he was the first abbot-bishop of a richly endowed monastery that flourished for centuries. The cathedral of Longford is dedicated to Mel, as is a college. A crozier believed to have belonged to Saint Mel was found in the 19th century at Ardagh near the old cathedral of St. Mel. The crozier is now kept at Saint Mel's College in a darkened bronze reliquary that was once decorated with gilt and colored stones.

St. Mel died in approximately the year 489, and his feast day is celebrated on February 6.