Early childhood educators and their experiences are often unheard and undervalued. To help provide this voice, this study utilizes a non-experimental qualitative case study design that highlights and deepens the context of teachers’ perspectives on support of social-emotional learning and classroom dynamics and the impacts of student behavior on teacher identity development in multi-age and single-age classrooms. Eight teachers from four private preschools were interviewed either in person or virtually and were asked 12 questions on topics related to classroom dynamics, support for social-emotional learning, classroom routine, and teacher reward and dissatisfaction. Teacher responses were recorded, transcribed, and analyzed through three coding cycles. Two major hypotheses were formed from the codes: teacher identity development is positively reinforced when students exhibit self-regulatory social-emotional classroom behaviors that can be positively and negatively impacted by age grouping, and teacher identity development is negatively reinforced when students demonstrate a lack of self-regulatory social-emotional classroom behaviors that can be negatively impacted by age grouping. The findings discussed within this study highlight the impact that student behavior has on teacher identity development and the complexity that is added from differing age groups