According to the literary scholar Hugh Kenner, "every theme in the entire life-work of James Joyce is stated on the first two pages of the Portrait". The highly condensed recounting of young Stephen's growing consciousness "enact[s] the entire action [of the novel] in microcosm. An Aristotelian catalogue of senses, faculties, and mental activities is counterpointed against the unfolding of the infant conscience", and themes that run through Joyce's later novels find expression there.
The epigraph quotes from Ovid's Metamorphoses: the inventor Daedalus, who has built a labyrinth to imprison the Minotaur, and his son Icarus who are forbidden to leave the Island of Crete by its King, Minos. Daedalus, "turning his mind to unknown arts", fashions wings of birds' feathers and wax with which he and his son flee their island prison. Icarus flies so close to the sun that the wax on his pair melts and he plummets into the sea. To A. Nicholas Fargnoli and Michael Patrick Gillespie the epigraph parallels the heights and depths that end and begin each chapter, and can be seen to proclaim the interpretive freedom of the text.
A Portrait belongs to the genres of Bildungsroman, the novel of education or coming of age, and Künstlerroman, a story of artistic development, of which A Portrait is the primary example in English.
Stephen Hero is a directly autobiographical novel, including people and events because Joyce had personally experienced them. In contrast, in A Portrait Joyce refines his approach by selectively drawing on life events and reflecting them through the consciousness of Stephen Dedalus, a fictional character.