This article begins with the intent of trying to understand the meaning and principle of character education in the perspective of Toegye’s neo-Confucianism. It attempts to read the understanding of character education expressed in Toegye’s seminal work, the Seonghaksipdo (“Ten Diagrams on Sage Learning”). It is not too much to say that the Seonghakshipdo is a work on the topic of character education insomuch as it systematically demonstrates the meaning of character, the way of education for its actualization, and everyday learning. Character in Toegye’s neo-Confucianism refers to human original nature itself, understood in terms of benevolence, righteousness, propriety, and wisdom rooted in the ‘sacred’ source of existence. Arguments of the substance-function and heartmind-nature rationales surrounding this position are included in the first(Taegeukdo), second(Seomyeongdo), sixth(Simtongseongjeongdo), and seventh(Inseoldo) diagrams. Next, the curriculum of the Elementary Learning and Great Learning envisioned as the way of education for actualizing character is discussed in the third(Sohakdo), fourth(Daehakdo), and fifth(Baeknokdonggyudo) diagrams. Finally, the eighth(Simhakdo), ninth(Gyeongjaejamdo), and tenth(Sukheungyamaejamdo) diagrams illustrate the ideal of manifesting character in all aspects of everyday life, taking the embodied study of gyeong(mindfulness) as the method of practice. Based on the Seonghaksipdo, from the perspective of Toegye neo-Confucianism, character education as education for the manifestation of human original nature is not just an aspect of education but education itself. The common contemporary perspective that limits character education to ‘moral education,’ as that which contrasts with ‘knowledge education,’ is narrow-minded. Furthermore, it is suggested that character development is not just a matter of formal curriculum, but the most fundamental task of education to be achieved in all times and places of everyday life.