In the field of second language learning motivation, the studies on process-oriented nature of possible L2 selves are scarce. In order to address this research gap, this study explored how a group of five Chinese non-English-major undergraduates developed their possible L2 selves during the transition year from high school to university. The content analysis of 4 focus group interviews, 202 journal entries, and 50 post-diary interviews show that in the first academic year, the five participants experienced a four-stage cyclical process of developing their possible L2 selves, namely, (a) generating multiple possible L2 selves, (b) selecting a possible L2 self to pursue, (c) realizing the selected possible L2 self, and (d) incorporating the realized possible L2 self into the present self scheme. More specifically, the selected possible L2 self was realized through elaboration of relevant imagination and alignment with a larger community. The study has enriched our understanding of the mechanism of possible L2 self development and shed light on motivating undergraduates to learn English in an EFL context.