While it is well established that the ability of teachers to build cultural competence is a critical aspect of their work especially in urban and highly diverse settings, the kinds of experiences that help them build cultural competence is less clear. The author attempts to contribute to this void by showcasing a White, science teacher's experiences in building cultural competence in a highly diverse urban school. Culturally relevant pedagogy is used as an analytic tool to explain and uncover the ways in which the teacher develops cultural knowledge to maximize student learning opportunities. The basic premise of the article is that this White teacher was able to build cultural congruence with his highly diverse learners because he developed cultural competence and concurrently deepened his knowledge and understanding of himself and his practices. Practicing teachers, teacher educators, and researchers are provided a picture of how the teacher builds relationships with his students, how he deepens his knowledge about how identity and race manifest in the urban context, and how he implements a communal and collective approach to his work as he builds cultural knowledge and cultural competence about himself, his students, and his practices.