This narrative inquiry investigates an English as a Foreign Language teacher's storied experience of 30-year extensive reading (ER) implementation, with the aim of exploring the formation of language teacher identity (LTI) of this individual teacher. Two narrative interviews were conducted, respectively focusing on the holistic story and detailed accounts of some critical incidents and significant others. Two researchers played different roles: one "insider," conducting, transcribing, translating, and analysing interviews; one "outsider," analysing the data with a relatively neutral perspective. Data analysis adopted an ecological approach and a three-level framework (societal, interpersonal, and intrapersonal levels). Findings highlight the complex links between discursive features, personal experience, teacher emotions, and power differentials in shaping the dynamic and multi-faceted nature of LTIs. Meanwhile, the considerable evolution of the teacher's ER implementation validates the importance of teacher training, especially opportunities for teachers to gain experiential knowledge which further contributes to teacher identity development.