Despite his popularity, the Rev. James S. Gale has not been given sufficient scholarly attention. How could it be? It appears that while Gale has been known as a missionary and a scholar of Korean studies, this two-fold identity has not been appreciated in a comprehensively way: scholars tend to interpret two aspects of his identity as contradictory ones or simply juxtaposed ones rather than as mutually interacted ones. In this context, in the area of Korean studies, they have seen him mainly as a Korean expert, without paying attention to his being a missionary; on the other hand, in the realm of Korean Christian studies, they have largely viewed him as a missionary, without properly relating this to his expertise in Korean studies. This article aims to overcome this discrepancy in the understanding of Gale in the contemporary studies, secular and Christian, in Korea. The thesis of this article is that the mutually integrated two-fold identity of Gale is the key to the understanding of his thought and work; that is, he was a scholar of Korean studies as a missionary. Such characteristics of his being a scholar of Korean studies as a missionary can be summarized as follows: first, he prepared himself as a missionary in Korea through cultural identification, through which he gradually overcome his paternalism; second, he equipped himself with expertise in Korean studies, which enabled him to be a first-class cultural missionary, namely, a theologian of missionary indigenization; and last, he bequeathed his legacy as a missionary scholar, which paves the way for Korean studies as mission. Thus, he challenged the understanding of both missionary works and a missionary.