He was born in Galata of Constantinoupolis and was ordained by the patriarch Theoliptos. Before becoming a Patriarch, he was Metropolitan of Nicomedeia.
Among the various measures that Dionysios II took in order to improve the financial situation of the Church was to send the Metropolitan of Caesaria Metrophanes in the West and in Venice for fund-raising. He, however, following the advice of the uniat bishop of Hersonisos of Crete Dionysios Zannetinos, came into communion with the pope of Rome Paul III and "did what God did not want". Therefore this mission provoked a tempest of complaints and problems not only against Metrophanes, but also against the patriarch Dionysios: that is why both were deposed.
The unfair condemnation of Dionysios, however, was never executed, and the patriarch kept his throne until his death in 1555. During his patriarchy, many matters of the Church were solved. The patriarchate and the education of the enslaved Nation received his kind attention; all the sources confirm that he was well-educated. His grave is found in the Monastery of the Kamariotissa on the island of Chalki, one of the Prince Islands.