Eric Erikson (1902-1994) was an early psychodynamic theorist whose theory of personality incorporated Sigmund Freud's. His post-Freudian theory extended Freud's infantile developmental stages into adolescence, adulthood, and old age. Erikson suggested that at each stage a specific psychosocial struggle contributes to the formation of personality. From adolescence on, that struggle takes the form of an identity crisis - a turning point in one's life that may either strengthen or weaken personality.

Erikson was fueled in his studies of personality and identity crisis mainly by his childhood. A sickly child, Erikson lived alone with his mother until he was three years old. On his third birthday, his mother married Dr. Theodor Homburger, a Jewish pediatrician from Karlsruhe, a town in southern Germany. Erikson grew up believing he was Homburger's son. However, as Erik matured, he began to realize that this was incorrect because his blond hair and blue eyes did not match the features of either his mother nor Homburger. He pressed his mother for an explanation, but she lied to him and said that Valdemar Salomonsen, her first husband, was his biological father and that he abandoned her after she became pregnant. As Erikson grew older, he learned that Salomonsen's marriage to his mother did not even last one night and was probably never consummated. Salomonsen left Erikson's mother four years before his birth, so he couldn't have been the father. Finally, Erik chose to believe that he was the outcome of a sexual liaison between his mother and an artistically gifted aristocratic Dane. Erikson believed this for the remainder of his life, but he was always fueled by the search for his biological father.

Erikson ventured away from home during late adolescence, adopting the lifestyle of a wandering artist and poet. After nearly seven years of drifting, he returned home. At this time, an event happened that changed his life. He recieved a letter from his friend Peter Blos inviting him to teach children in a new school in Vienna. One of the founders of the school was Anna Freud, who became not only Erikson's employer but also his psychoanalyst. After teaching at the school, studying Freud's theories, and researching on his own, he developed his own theory of personality. Unlike earlier psychodynamic theorists who severed nearly all ties to Freudian psychoanalysis, Erikson's theory was meant to extend Freud's Stages of Development.