At the beginning of the novel, Alexias and Lysis are both already close to the Hellenic ideal, in appearance, accomplishments, and aspirations. They are engaged, with the full approval of Alexias's father, in the classical relationship of Greek homosexuality, in which Alexias is the ἐρώμενος, the younger beloved, and Lysis the ἐραστής, the older lover. This was regarded in Athenian culture as more important than marriage in terms of intellectual and emotional development. The ἐραστής is a philosophical guide as well as a lover, so it is fitting that Lysis introduces Alexias to his own mentor, none other than Socrates.

Alexias's intellectual and moral growth are particularly evident throughout the book. He is generally obedient to his father, Myron, who is a good man but thoroughly constrained by convention. Myron commands Alexias that if his stepmother gives birth to a daughter, he is to take the girl and leave her to die of exposure in the mountains. This was a common practice at the time, and most boys would have obeyed without question, but Alexias chooses the higher virtue of compassion over filial obedience.

Alexias and Lysis both show their courage in the Peloponnesian War, and Lysis later dies heroically in battle. Alexias again shows his compassion by caring for Lysis's widow, whom he later marries. Both men think seriously about their duty, and the effect of their actions on the state and on themselves, showing independence and integrity as they follow their ideals.