This article explores experiences that led individuals to become teacher leaders advocating for under-served students in urban schools. Cohort members in an urban teacher leadership master's degree programme engaged in systematic critical reflection about becoming leaders for equity, describing the influences of their families and communities, positive and negative experiences in school, and the importance of leadership opportunities provided within and beyond school. Being marginalized as students influenced their activism and their commitment to teach in their communities. Vignettes or cases show how teachers' professional identity was powerfully shaped by educational interactions influenced by differences in race, class, gender, and language. These urban teachers take leadership by advocating for marginalized students and their families and are truly activists for social justice.