This is a longitudinal study of foreign language teacher professional identity development. We traced a single teacher's sociohistorical identity development at three temporally different moments during the first eight years of his teaching profession. The data, collected mainly through classroom observations and semi-structured interviews, were analysed through the cumulative lens of the communities of practice theory, the possible selves theory, and positioning theory, which provided an integrated conceptual framework at the levels of theoretical principles, methodology, data analysis, and interpretation. The findings revealed that, as a result of the teacher's evolving community of practice, each of the three moments over the eight-year period exemplified a change in the constellation of his possible selves and in how he positioned himself and others in his professional environment. The results of this study substantiate a multi-perspectival approach to understanding teacher professional identity development and highlight the significance of attending to teachers' realignment of possible selves and repositionings.