Augustine is the narrator of The Confessions and its chief protagonist. He is a man of great intelligence, has a burning desire for knowledge, and his "restless heart" leads him through several stages of seeking. He arrives at the truth he is looking for within the philosophical and theological framework of Roman Catholicism. Augustine describes his experience of direct apprehension (understanding) of God and uses his own story to exhort those following faulty belief systems (in his view) to join him in embracing the orthodox Christian faith.
God is personified in The Confessions as Augustine's spiritual Beloved. Augustine understands that God is not a material being, but because it is impossible to have a dialogue with God without imagining him in human form, this is what Augustine does by addressing him, as if they are having a dialogue. God is the recipient of Augustine's praise, love, questions, repentance, speculations, insights, and so forth, which the author pours into God's hypothetical ear.
Monica is Augustine's mother and a devout Christian. When she comes to Rome, she is instructed by Ambrose, and later she becomes part of her son's circle of seekers. Monica prays incessantly that Augustine will convert to Catholicism, and she sometimes has prophetic dreams inspired by God. She also has worldly ambitions for her son, but she gives them up after Augustine's conversion and decision to embrace celibacy and a life of renunciation. She also shares a mystical experience with her son before she dies.
Bishop Ambrose is Augustine's spiritual mentor when he arrives in Milan. Ambrose, a married family man as well as bishop, is highly educated and a gifted preacher. He has read the Neoplatonic texts that teach God is an immaterial being, and he is teaching his Catholic parishioners this doctrine, which he has integrated into Catholic theology. He doesn't have much time to talk to Augustine directly, but Augustine finally is able to understand the Christian scriptures metaphorically and allegorically as a result of his exposure to Ambrose's Neoplatonic teachings.
Alypius is Augustine's best friend, who follows him in all things. He follows his friend first into Manicheism. Alypius is honest and gentle, and he has no trouble maintaining celibacy. Nonetheless, he becomes addicted to watching bloody gladiatorial games. Augustine is able to help him overcome his addiction. Alypius is present when Augustine gets a sign from God that it is time to convert to Catholicism and become celibate. Alypius follows his friend in this decision, and the two are baptized together.