Og Gwan-bin (1891-1933), a Korean independence activist, was sentenced to jail by the Japanese colonial government for his involvement in “105 People Incident”, a predominantly Christian nationalist movement in 1911. This movement had laid the bedrock for the "March-First Movement" of 1919 for national independence. After the "March-First Movement", Og rushed to Shanghai as an exile where he got involved with the Korean interim government. Afterwards, Og converted to Buddhism and became a disciple of Master Taixu. Their collaboration aimed at the reformation of Buddhism, and in later years Og’s medical company Fo Ci (佛慈) commercialized the improvement of the Chinese medicine adapting scientific methods of refining treatments. However, Korean anarchist clique suspected Og of espionage for the Japanese and assassinated him in public. His complicated life was overshadowed by changing identities: from Korean nationalist to Chinese citizen by choice, from Christian agitator to Buddhist reformist, and from independence activist to suspected traitor of his native Korea. Foregrounding Og Gwan-bin’s changing roles, this paper aims to reconcile partisan debates between Chinese and Korean scholars, each claiming the resourceful innovator for their nation. For example, according to the Japanese imperialism document at the time and the book of South Korea's "Uiryeong Og Si Daedongbo", it was verified and supplemented that his ancestral home is Korea. At the same time, this paper explores his close relationship with the master of Taixu, such as his active help and support for the Buddhist reform movement promoted by Taixu, and the humanistic Buddhism. Moreover, this article talked about the main motive of Og's creation of medical company Fo Ci (佛慈). It was for not only helping the civilians and the proletariat, but also promoting the spread of Buddhism. In addition, Og Guan-bin had worked hard to rebuild the Hangzhou Goryeo-sa, which was built by the Daegakguksa Ui-cheon of the Goryeo Dynasty, and has actively promoted the reconstruction of the Goryeo-sa into a future-oriented Korean-Chinese Buddhist exchange. In short, he laid the foundation for the important contribution of the modern Chinese Buddhist community and the humanistic buddhism thoughts. In the process of modern Korean-Chinese Buddhist exchanges, Og Guan-bin played an extremely important role.