Early childhood mental health consultation (ECMHC) is a capacity-building intervention that aims to enhance the quality of young children’s affective environments in order to promote children’s social, emotional, and behavioral health. In this study, the effects of ECMHC on children’s social–emotional and early academic outcomes over the course of one academic year were evaluated in 20 classrooms (15 intervention and 5 comparison) with 38 teachers (29 intervention and 8 comparison), and 390 children (282 intervention and 108 comparison; Mage = 46.71 months old) across 3 schools. Observations, teacher ratings, and direct assessment were used to evaluate children’s social–emotional skills and early academic outcomes. A three-level model that accounted for the nesting of children within classrooms within schools found that children in intervention schools had more positive classroom behavior, fewer observed social–emotional challenges, and higher academic achievement in math, literacy, and writing at the end of the school year. Our findings suggest that this model of ECMHC is an effective way to spread out the expertise of mental health professionals and improve the social, emotional, and academic outcomes for children in the school setting. This is particularly important for marginalized and under-resourced communities who often face higher levels of adversity and mental health needs with fewer available resources as a result of structural factors including racism and underinvestment of public funds.