This study qualitatively explored the process of student environmental identity development (sEID) within the highly social and structured context of elementary school science. Social practice theory was used as the lens to distinguish the dimensions of sEID that were visible during a curriculum-based, in-school program focused on the issue of pollution. Student narratives, collected from small group interviews and reflective journals, were prioritized to capture the process of students in context identifying as "being "for" the environment." Data collected from 35 grade six students were qualitatively coded, a network diagram was used to visualize the relationships in the data, and a research vignette was constructed. Eight dimensions were recognized as contributing to sEID; the opportunity to be an environmental actor with peers, increased awareness of environmental threat, emotional responses, self-recognition for environmental action, perceived agency, changed behavior across social contexts, social recognition for identity actions, and personal meaning. While many of these dimensions have been directly or indirectly discussed in the research on adult environmentalists, shifting the emphasis from group membership to the individual student in context led to the addition of two dimensions--personal meaning and emotional responses. Recognizing the eight dimensions of sEID is an important contribution to the literature as students engaging in environmental action as a requirement of school is distinct from the existing research. Identifying the dimensions of sEID can support the intentional design of learning sequences that foster environmental identities in school and beyond.