Using data from 832 kindergarten and first grade primary teachers and 662 of their students, the current study investigated teachers' use of behavioral and instructional classroom practices and whether these strategies moderated associations between teachers' expressions of positive and negative classroom emotion and students' social-emotional and behavioral competence. Results indicated that teachers' positive expressiveness positively predicted young students' social competence and was inversely related to negative child outcomes, irrespective of teachers' behavioral and instructional classroom management practices. In contrast, teachers' negative emotional expressiveness positively predicted students' anger/aggression, but only when teachers reported using controlling and teacher-centered approaches to classroom behavioral management. At the same time, teachers' negative expressiveness predicted low levels of student anger/aggression when teachers reported more child-centered instructional management approaches. Findings contribute to the understanding of the intersection of teachers' expressiveness and their classroom management practices for explaining children's social-emotional and behavioral competence in early childhood classrooms.