Socrates is the main speaker in the dialogue, and he largely controls the direction that the conversation between Phaedrus and himself takes. He sets off the conversation by requesting to hear the speech of Lysias that Phaedrus is carrying, and then tries to improve on that speech in several ways. In attempting to argue the same position more effectively (his first speech), he shows himself to be a more effective speaker than Lysias; in attempting to argue the opposite (his second speech), he shows himself to be much more imaginative in his use of myths and allegories. Socrates shows a meticulous concern for beginning at the root of a problem, making his definitions and assumptions clear before reasoning any further.

As a character, he frequently claims to know little or nothing, a point which, even if true, contrasts ironically with his insistence on clarity in thought and his love of knowledge. He feels a particular duty to gods and spirits, even claiming to receive a supernatural sign that prevents him from leaving Phaedrus without having sufficiently praised the god of Love. His insistence that he really knows very little is perhaps genuine or perhaps falsely modest; in either case, it helps him escape responsibility for whatever consequences his speeches may have.