This dissertation explores what happens to American-trained Taiwanese English teachers when they return to teaching in Taiwan. Using a method of "collective biography", it inquires into three American-trained Taiwanese English teachers' life stories and the researcher's own as an American-trained Taiwanese English teacher and researcher. I focus on the relationships among the construction of identity, language and the hidden power of English as a global language. The one year long research process consisted of classroom observations and interviews with the participating teachers and some randomly selected students from these teachers' classes. By providing a combination of an in-depth descriptive analysis and additional theoretical interpretations of the data and the researcher's self-reflexive analysis, this study unravels their struggles and tensions of the three teachers through their reflections on their teaching goals and pedagogical practices. On the one hand, these American-trained Taiwanese teachers reinforced the ideology of English as a tool for economic and social leverage through the content and teaching methods they used in their classrooms. On the other hand, upholding such a view of English for global competitiveness became a constraint on their teaching practices and threatened their professional identity development. Throughout this trajectory, my self-reflexive narratives were interwoven within the narratives of these teachers' stories. At the same time, my self-reflexive narratives revealed how I responded to these teachers' struggles and tensions and my dilemmas and uncertainty as a researcher. To sum up, this dissertation is a collective work of our "sweaty fight" for meanings and "response-ability" to our experiences as American-trained Taiwanese English teachers who have returned home to teach. To better understand these American-trained Taiwanese English teachers' challenges given the current context of globalized English education, I suggest that it is essential to engage more deeply with three key concepts: critical reflexivity, transformation and local perspectives. In conclusion, I provide pedagogical/curricular suggestions and future directions for teacher education research. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]