This study aimed to examine the connection between heritage language and ethnic identity. For this purpose, the novel Native Speaker, written by a Korean American author, Chang-rae Lee, was chosen as the main text. The study’s relevance comes from the fact that a person’s participation in the cultural activities of their ethnic groups can be determined by several variables, among which language is most strongly associated with ethnic identity. This qualitative analysis is based on Tse’s ethnic identity stage, which describes how attitudes toward identity evolve. The stage begins with ambivalence toward one’s ethnicity, followed by engagement with the quest for the significance of ethnic identity and, eventually, its attainment. The protagonist of the book is a second-generation Korean American man who exhibits an insecure identity. The story delineates the stage of ethnic ambivalence that arises from being cut off from one’s ethnic culture and unable to integrate into the majority group. Through extensive reflection on interpersonal interactions and reconciliation with his heritage language, the main character ultimately finds an integrated identity. The results indicate that heritage language serves as a means of building ethnic identities among minorities and enhancing their sense of social integration. When their heritage languages are valued and acknowledged, minorities can forge a strong ethnic identity.