As a part of longitudinal qualitative research project, this case study is an examination of how one Korean EFL teacher, an English enthusiast, developed his multiple identities within his school, home, and social communities. Examination of his trajectories in these domains sheds light on how the native-speakerism ideology prevailing in Korea had influenced the non-native English-speaking teacher's identity development and was affecting his life as a language learner, a language teacher, and a parent. Three of his identities emerged from this study: a language learner who was struggling to join the community of native English speakers, a language teacher who was seeking students' validation of his qualifications as a good English teacher, and a parent who expected his children to achieve his long-sought but seemingly unattainable goal of having native-like English proficiency. However, these identities were neither passively stable nor fixed, but rather were being constantly and actively negotiated. The findings suggest the necessity of taking a critical perspective on definitions of native speakers, on the impact of native-speakerism on the professional identity construction of non-native English-speaking teachers in EFL contexts, and on its effects on their domestic and social lives.