Modeled after Joyce himself, Stephen is a sensitive, thoughtful boy who reappears in Joyce's later masterpiece, Ulysses. In A Portrait of the Artist as a Young Man, though Stephen's large family runs into deepening financial difficulties, his parents manage to send him to prestigious schools and eventually to a university. As he grows up, Stephen grapples with his nationality, religion, family, and morality, and finally decides to reject all socially imposed bonds and instead live freely as an artist.

Stephen undergoes several crucial transformations over the course of the novel. The first, which occurs during his first years as Clongowes, is from a sheltered little boy to a bright student who understands social interactions and can begin to make sense of the world around him. The second, which occurs when Stephen sleeps with the Dublin prostitute, is from innocence to debauchery. The third, which occurs when Stephen hears Father Arnall's speech on death and hell, is from an unrepentant sinner to a devout Catholic. Finally, Stephen's greatest transformation is from near fanatical religiousness to a new devotion to art and beauty. This transition takes place in Chapter 4, when he is offered entry to the Jesuit order but refuses it in order to attend university. Stephen's refusal and his subsequent epiphany on the beach mark his transition from belief in God to belief in aesthetic beauty. This transformation continues through his college years. By the end of his time in college, Stephen has become a fully formed artist, and his diary entries reflect the independent individual he has become.