As young people experience challenging climate events, they may feel powerless to shape the future and uncertain about STEM-based solutions. This project focuses on the potential of place-based learning, field science, and digital storytelling to nurture diverse middle school youths’ environmental agency, STEM career knowledge, and STEM identities. The project includes out-of-school STEM learning to investigate the history, ecology, and restoration of a local watershed. The watershed has unique biodiversity and is increasingly impacted by negative climate events in a city experiencing rapid population growth. Youth create stories about the land, water, people, and history of the watershed using podcasts, augmented reality, and digital zines. Digital storytelling allows youth to recapture a sense of agency amidst climate anxiety as the stories’ digital and mobile nature can reach diverse audiences and encourage multiple ways of knowing about a socioecological system. A primary contribution is a grounded theory of identity play, which involves youth exploring new roles and self-narratives that challenge societal expectations or current personal narratives. Identity play is nonlinear, not always predictable, and horizon-expanding. Identity play allows us to design for multiple STEM entry points and pathways, recognize the productivity of youths’ decisions not to pursue certain pathways, and explain impacts of out-of-school STEM experiences on diverse youths’ career choices.