This longitudinal case study utilizes critical event narrative methodology and intersectionality to examine the experiences of one female Caribbean teacher as she sought to enact her vision of socially just science education in secondary schools in the USA. This research explored how the convergence of racial, cultural, and science teaching identities within unique educational contexts shapes teacher beliefs and instructional practices in teaching science for social justice. Data collection spanned 3 years, including 1 year in a teacher education program and 2 years of in-service teaching in urban schools. Data sources included periodic interviews, lesson plans, and written reflections. Analysis focused on what the teacher identified as critical events, how she made sense of the event, and how she changed her beliefs and/or instructional practices to enact her vision of justice. Findings are presented as two overarching identity-based themes exemplified in critical teaching events. Findings offer insight into the role of intersectional social power dynamics in teaching science for social justice, particularly in considering issues of access and instructional quality. This study has implications for attending to the complexity of science teacher identities in teacher learning about social justice for pre-service and in-service teachers.