His name, Benedictus, means "Blessed" in Latin. He was born in 480 in Nursia, a small town northeast of Rome. He had only rudimentary schooling: he wrote later of his fear that through book-learning he might 'lose the great understanding of my soul.' At an early age he fled to a monastery where he was tonsured; he then withdrew to a remote mountain, where he lived or several years in a cave, perfecting himself in prayer. His only food was some bread brought to him by Romanus, the monk who had tonsured him. When he became known in the area, he fled his cave to escape the attentions of the pious; but flight proved useless, and in time a community of monks formed around him. He was granted many spiritual gifts: he healed the sick and drove out evil spirits, raised the dead, and appeared in visions to others many miles away.

Benedict founded twelve monasteries, most famously that at Monte Cassino. Initially, each monastic house had twelve monks, to imitate the number of the Twelve Apostles. The Rule that he established for his monks was based on the works of St John Cassian and St Basil the Great, and became a standard for western monasteries. Thus he is sometimes called the first teacher of monks in the West.

Six days before his death, the Saint ordered that his grave be opened, gathered all his monks together, gave them counsel, then gave his soul back to God on the day that he had predicted. At the moment of his death, two monks in different places had the same vision: they saw a path from earth to heaven, richly adorned and lined on either side with ranks of people. At the top of the path stood a man, clothed in light and unspeakably beautiful, who told them that the path was prepared for Benedict, the beloved of God. In this way, the monks learned that their abbot had gone to his rest.