This study aims to provide a more balanced approach to Dasan Jeong Yak-yong’s understanding of Sangje (Lord on High) as the ultimate reality by integrating the existing conflicting theories on Sangje in Dasan’s tenets of Confucianism. It also attempts to make the best use of various views posited in previous studies, with an analytic focus on Dasan’s personal reasons for placing the concept of Sangje at the core of his Confucian theoretical system. Research on a scholar should first deal with their formation of thought and background as an individual, and thus the content and direction of Dasan’s thought, the context of his life that influenced his problem awareness and his thinking, and the mode of thinking embodied in him through his life experiences are included in the scope of this analysis. In particular, this article examines the transformation of the Confucian system Dasan sought through his concept of Sangje, the background of the formation of his view on Sangje, his conception of Sangje, the direction of his thought, and the significance of his approach to the ultimate reality.