Since the first of his novel, The Poorhouse Fair(1959), John Hoyer Updike has made many other publications has been the Rabbit Series that had been created aver a cycle of 10 years and they are all recognized as the criticism of the late 20th century American society. One reason the series were so recognized by many literary scholars was because it had described the agony and conflict within the American home and the life of the middle class people. From the end of the 1990`s to that of the 1980`s, the character of Harry "Rabbit" Angstorm, has been an example of these conflicting and agonizing lifestyles of the late American Society. Harry Angstrom, the hero of the Rabbit Series, represents the reality of human being struggling for existence and dangerous to understand the world of Updike`s wide and various works with the limited theme of alienation. This study will describe aspects of Existentialism that Harry, the hero of the Rabbit Series, feels through his behavior and consciousness in the modern American Society. In Rabbit, Run, Harry is in the existential dilemma. As he becomes more excessive with the existential self-consciousness, Harry`s feeling of alienation becomes deeper and more serve. This type of alienation that Harry is feeling is an aspect of mental alienation than that of the physical or environment conditions that can also cause alienation, In Rabbit Redux, Harry, who rejects to be restricted to a standard of values other than his own inherent self and inner desires, exerts the independent self-will to choose and to be responsible to all matters. However, he becomes the existence of isolation and alienation for security to which cannot be permitted as results of alienation. In Rabbit Is Rich, Harry feels the conflict and the sense of alienation in relations to his son because of his sense of guilt, anger and jealousy towards his son. Rabbit at Rest, the last work of the "Rabbit" Series, is mainly composed of Harry`s death Accordingly, it deals with how Harry accepts the absurdity of death, when he searches for the meaning of life and existential identity. Harry`s agony and wandering are rooted in the Western individualistic existentialism Harry seceded from home and social consolidation was to exercise his right as a liberated subject, but the constant struggles of isolation and alienation becomes the reality which cannot be governed by the relative existence and the consequence resulting in the existential absurdity. That is, it leads to his feelings of emptiness and fear of death.