Konjo is the willpower necessary to endure suffering, and for making an effort, having become a word in daily use in society, as well as in sports. The purpose of this study was to clarify the opportunity and the factors responsible for the transformation of konjo in Japanese society in the 1960s. Our study focused on three points: 1) Clarifying how the meaning of the word konjo changed in the 1960s, from its dictionary definition and usage in newspaper articles. 2) Clarifying the situation in which konjo became popular through the Tokyo Olympic Games, and its spread to the sports community and to society. 3) Considering the factors responsible for the transformation of konjo, and to propose a hypothesis that could account for it. Our conclusions were as follows: 1) The meaning of konjo evolved from a negative context of “a fundamental character and mindset with which a person is born” to a positive context of “a strong, resilient character that cannot be suppressed” and “a strong motivation to accomplish an aim” at the beginning of the 1960s. 2) Konjo was considered to the spiritual keynote for athletes at the Tokyo Olympic Games. Hirobumi Daimatsu's “konjo theory” had the persuasive reason by winning “Oriental Witches” championship at the Tokyo Olympics. In view of these factors, we considered that konjo was interpreted as a popularized moral virtue by society, and impacted on both education and popular culture. 3) We considered that the concept of konjo became transformed and was used to promote competitiveness in sports at the Tokyo Olympics as part of the strategy for “character building”. It also played a role in bolstering human resources that played a key role in economic development during the 1960s, and thus was of strategic value. The considerations listed above show that the Tokyo Olympic Games played an important role in the transformation of the concept of konjo in the 1960s.