This essay examines the connectedness between cultural trauma theory and decolonial studies in pastoral theology, demonstrating the denotation of collective trauma in South Korea and Korean Christianity from past colonial and war experiences. Although cultural trauma theory is well established in studying the case of the Holocaust and Western context, it has not yet explored the trauma of the Third World in a fully fledged manner. Rather, it still employs a Western-centered discourse that is unable to explain the disparity of power dynamics based on colonial values. Therefore, a critical analysis is essential to develop a decolonial discourse between cultural trauma theory and pastoral theology. The case of Korean cultural trauma and its relation to Korean Protestantism is a good starting point for addressing decolonial pastoral care in that the Korean church is still complicit in the colonial religious inheritances concerning its colonized ways of thinking and psyche. Throughout this essay, I argue that Korean social identity and Protestantism are reproducing the harmful reaction of in-group exclusion under the impact of cultural trauma. Finally, I provide a pastoral theological analysis of this discussion in order to suggest a new possibility of decolonial pastoral care for the traumatized Korean society and Christianity.