Felix Krull begins his "confessions" at the beginning, with his family background and infancy. He comes from an upper class family in the Rhine Valley; his father owned a small manufacturing concern; he has an older sister named Olympia. Felix writes about his childhood love of fantasy, as exemplified by his love of dressing-up in costumes at home and his passion for the theater. He detested school, however, because it was so unremittingly boring.

Felix first practiced the art of deception by forging his father's penmanship on notes excusing him from school because of sickness. Later, he graduated to "performing" the illness by being able to fool his mother with imaginary symptoms. In fact, he was so good at "performing" that he was actually able to create the symptoms in himself (e.g. nausea and vomiting), and in so doing, "I had improved upon nature, realized a dream . . . " When the doctor arrived to examine Felix, the doctor initially assumed that it was a phony case (just being "school-sick"), but Felix was able to convince the doctor as well, or at least force enough doubt that he went along with the ruse.

Among the adolescent episodes that Felix confesses is his first theft (of chocolates from a sweet shop) and his first sexual experience (with a much older housemaid). He cites the latter event in the context of explaining how his "great joy" over sensual experience is so much greater than that of the common person.

Felix Krull's confessions end with the family's bankruptcy and loss of their sparkling wine factory, and his father's suicide some months later: "I stood beside the earthly husk of my progenitor, now growing cold, with my hand over my eyes, and paid him the abundant tribute of my tears."