This study analyzes the theory and practice of the Silla Hwarangdo organization from the perspectives of organizational history, history of organizational thought, and historical organization studies, using modern organization theory. No prior study had examined the Hwarangdo organization from an organizational theory perspective. In this study, regarding the origin of the Hwarangdo organization—a major research topic—it was demonstrated that the Silla Pungnyu-Seon teaching corresponds to Danjeon breathing methods, that its founder was Seondo Sinmo (the Holy Mother of Seonanism), and that the prototypes of the Hwarang and Wonhwa organizations can be traced to King Bak Hyeokgeose Geoseogan and Queen Alyeong. As major organizational ideologies that influenced the effectiveness of the Hwarangdo organization, the study examined the organizational thought of "ruling the world through bright illumination," the organizational thought of promoting the nation's prosperity, and the organizational thought of the Five Commandments for Hwarang. Additionally, nine major theories influencing effectiveness were demonstrated: paternalistic organizational thought as the concept of the father-sovereign, democratic leadership of Y-theory and sage-king governance, the assessment center method and organizational life, meritocracy and the cultivation of the sa (scholar-warrior) class, self-actualization motivation and leading by example from above, team organization and learning organization types, adoption of coaching methods, modeling and status symbols, and thorough reward systems and the Sangsaseo organization. Regarding the practice of the Hwarangdo organization, it was demonstrated that their approach manifested as blitzkrieg warfare in the unification of Gaya, breakthrough warfare in the unification of Baekje, vanguard warfare in the annihilation of Japanese forces, logistics and breakthrough warfare in the unification of Goguryeo, all-directional warfare in the expulsion of Tang forces, and a combination of containment and cooperation with Balhae. The high effectiveness of the Hwarangdo organization is attributed to the rational organizational management of Silla's organizational theorists and practitioners, and in particular, the "bright organization" thought as an organizational ideology deserves to be inherited in the modern era.