This article discusses the anti-heroic protagonist Bloom as a Jewish other in Ulysses, who stands on the position of the racial-ethnic border between the Irish and the Jewish. From the beginning of the publication of Ulysses, Bloom`s ambiguous Jewish identity has been one of the major controversial discussions among the Joycean scholars. While the early Joycean scholars has, on the whole, accepted what Joyce said about Bloom`s Jewishness and developed their interpretation of Ulysses on the ground of it, some of the later scholars raised a serious questions about it. They have argued that Bloom is not Jewish by religious, anthropological, and social criteria. Against these arguments, this study emphasizes Joyce`s intentional ambiguity of Bloom`s Jewish identity, which generates the metaphoric significance of the modern wandering Jew in the post-colonial context of Ulysses. Like all important modernists whose works address postcolonial questions, Joyce was critical of the constraining oppressive constructs of selfhood that arouse from both colonial subjugation and the ethnoracial-nationalist programs that reacted against it. In confronting this binary, Joyce became interested in the interstices of racial, ethnic, gender, and nationalist identity. In his choice of the assimilated Irish jew as a hero of his work, he depicted the marginal ambiguous Jew as a trope for the doubly-colonized subject. In the "Cyclops" episode, Bloom`s ethnic identity was portrayed as the non-Irish Irishman as well as the non-jewish jew. The doubleness of his identity positions him as a socially marginal victim and scapegoat in the Catholic/nationalist community of Ireland as shown in the "Cyclops" episode.