The purpose of this study was to explore the nature of requisite teacher knowledge for teaching lower-track science students. Using video accounts, student focus groups, and teacher reflections researchers documented missteps, dead-ends, and unfruitful trajectories informed by the teacher's incoming knowledge and compared these instances to necessary modifications informed by students' voices and cultural artifacts. Our study revealed the shifting nature of sociocultural and pedagogical content knowledge of the teacher immersed in a context unlike that he experienced as a student. Results showed that teachers of majority backgrounds could learn to teach diverse students with at least moderate success from the perspective of their students. Implications for research and teacher education in diverse settings are discussed.