This dissertation explores the reconfiguration of religion in modern global society with a focus on Koreans’ use of the category of religion. Using textual and structural analysis, this study examines how the notion of religion is structurally and semantically contextualized in the public sphere of modern Korea. I scrutinize the operation of the differentiated communication systems that produces a variety of discourses and imaginaries on religion and religions in modern Korea. Rather than narrowly define religion in terms of the consequence of religious or scientific projects, this dissertation shows the process in which the evolving societal systems such as politics, law, education, and mass media determine and re-determine what counts as religion in the emergence of a globalized Korea. I argue that, ever since the Western notion of religion was introduced to East Asia in the eighteenth and nineteenth centuries, religion was, unlike in China and Japan, constructed as a positive social component in Korea, because it was considered to be instrumental in maintaining Korean identity and modernizing the Korean nation in the new global context. In twentieth century Korea, the conception of religion was manifest in the representation of the so-called world religions such as Buddhism and Christianity, which were largely re-imagined as resisting colonialism and communism as well as contributing to the integration and democratization of the nation-state. The phenomenal clout and growth of Korea’s mainstream religions can be traced to an established twofold understanding that religion is distinctive, normal, and versatile, while indigenous traditions and new religious groups are abnormal, regressive, and even harmful. I have found that, since the late 1980s, a negative re-formation of religion has been widespread in the public sphere of South Korea, with a growing concern that religion may harbor a parochial attitude against the nation’s new strategies of development. Religion has been increasingly signified as antisocial, conflictual, and sectarian in newly globalized South Korea, because structuralized religious power, in particular that of Protestantism, gets in the way of autonomous evolvement of the secular societal institutions. As such, I conclude by suggesting that the definition of religion was multiply appropriated by the differences in local particularization in contemporary global society. Insofar as religion is regarded as incompatible with the changed location of the national society in the new global society, the semantics assigned to what is called religion continues to be degraded in contemporary South Korea.