“I really got to think about my background, their background, and how do we come together on something?”: One emergent mathematics teacher leader's reflexive journey with Social Justice Mathematics

This 2‐year qualitative case study focuses on one emergent mathematics teacher leader, Mr. Miller, and his conceptualization of Social Justice Mathematics (SJM). SJM is a justice‐oriented pedagogical approach where students simultaneously learn dominant mathematics and explore social injustices to take action toward justice. Using Rodriguez's (Journal of Research in Science Teaching, 1998, 35, 589–622) sociotransformative constructivism framework, findings illuminate how dialogic conversation, authentic activity, and metacognition supported Mr. Miller's reflexivity about his positionality, which he described as “upper middle class, highly educated parents, white, male,” in relationship to his students' positionality. He taught in a public charter high school in an urban city in the Northeast United States, where approximately 60% of students identified as Black, 30% white, 10% mixed race, 1% Asian American, 1% Latine, and less than 1% Indigenous, with 60% of students qualifying for free or reduced lunch. The article discusses of the importance of reflexivity for teachers and teacher leaders of all backgrounds, and especially when educators of dominant backgrounds work with students of historically marginalized backgrounds. The article calls for further research with more experienced mathematics teacher leaders of various backgrounds and contexts to further investigate justice‐centered mathematics teacher leadership.