Morita therapy was founded in 1919 by Shoma Morita (1874-1938) and is a systematic psychotherapy based on Eastern psychology. Since its founding 75 years ago, the treatment theory, treatment environment, treatment population and its cultural environment have been examined and modified in some areas. In this review, we first examine Morita theory and discuss the changes that have occurred in subsequent theories and methodologies. Our discussion presents the founding of Morita therapy and the characteristics of Morita theory; the practice of Morita therapy; Morita therapy from the perspectives of transcultural psychiatry and comparative psychotherapy; subsequent developments and modifications of Morita therapy; and the biological studies of Morita therapy. We attempt to clarify the universality and uniqueness of Morita therapy and provide a new framework for understanding Morita therapy.