This study aims to explore the process through that non-native (NNS) language teacher trainees gain their expertise and identities as Japanese language teachers based on their life stories. Life stories help individuals to understand themselves by reflecting on their life experiences, which could affect teaching practices. However, this area of inquiry is little investigatedamong NNS teacher trainees. The participants are 10 graduate students in Japanese language teacher training programs at a university in Korea. They were asked to write, "Why did I want to become a Japanese teacher?" In their life stories, they wrote about their learning experiences and their path towards becoming a teacher, among other topics. As a result, their views on language, learners and learning became clear by the stories they toldabout learning incidents. The NNS trainees' identities were explained in "an imaginedcommunity" or "imagined identity" framework (Norton, 2000; Norton & McKinney, 2011;Norton & Toohey, 2011). Their stories also show how they perceive their own potentiality as language teachers. Lastly, what this study implies for NNS language teachers and teachertraining are discussed.