He was born to pious and wealthy parents on the island of Zakinthos. Early in life he renounced his wealth and worldly honors to enter monastic life. His virtue became so well known that he was appointed Archbishop of Aegina, where he served for many years. In time, in order to retire to a life of solitude and struggle, he resigned and returned to his homeland where he entered a monastery in the mountains. Here he received the grace of performing miracles, and worked many healing and saving wonders among the people of Zakinthos.

A story from the Synaxarion reveals his character as one truly united to Christ: "He excelled above all in love of neighbour and in meekness. One day the murderer of the Saint's own brother, fleeing the law and the members of his victim's family, arrived at the monastery and begged Dionysius for asylum, little knowing to whom he was speaking. On gathering the reason for his flight and that his own brother was the victim, the man of God resisted with all his strength his natural grief and the temptation to avenge the crime. Imitating Christ, who pardoned his enemies and prayed for his persecutors, he received the fugitive with compassion, comforted him, exhorted him to repent and hid him in an out-of-the-way cell. When his pursuing kinsmen reached the monastery with the dreadful news, the Saint did not reveal that he knew it already, but did his best with words of peace to allay the wrath of his relatives and their desire for vengeance. As soon as they moved off, he let out the murderer (who was amazed and terror-struck before such superhuman goodness) and having provided him with victuals and money for his journey, he sent him away to work freely at the salvation of his soul."

The holy bishop reposed in 1622 after a long and painful illness. He has continued to work signs and miracles and to appear from time to time to the people of Zakinthos, who venerate him as their protector and patron.