A Portrait of the Artist as a Young Man portrays stages of spiritual developments of a young artist. Based on some mystical backgrounds, particularly Aquinas’s mystical aesthetics, and referring to theosophists like Bruno and Saint Augustine, Joyce comes to a kind of mystical aesthetics of art. He, accordingly, depicts a young artist whose aesthetic attitude is mystical, encounters epiphany, and becomes a mystic artist. This article analyses Joyce’s novel from the perspective of his mystical aesthetics and shows the stages of the artist’s spiritual perfection up to Divine perfection, which according to Joyce is the final stage of spiritual development necessary for being an artist. These stages are represented in spiritual developments of a young artist, Stephen Dedalus, in five chapters of the novel in which he achieves the position of mystical epiphany and artistic creativity. Finally, the article concludes that the artist’s aesthetics, passing through stages of ‘integritas’, ‘consonentia’, and ‘claritas’, achieves its ultimate perfection and, thus, he becomes a mystic artist.