Through relationship building and collaboration, Infant and Early Childhood Mental Health Consultation (IECMHC) aims to increase early childhood professionals’ capacity to promote children's mental health and reduce the use of exclusionary discipline practices. We conducted a three-year pilot study of a cross-system, embedded model of IECMHC to address gaps in the literature regarding provider and classroom outcomes. Using a matched-comparison group design, the study examined differences between staff in intervention and comparison programs in their ability to create classroom climates that promote children's social and emotional development and explored factors associated with classroom climates. A sample of 120 teachers participated in surveys over a 21-month implementation period. A subsample of teachers participated in classroom observations (n = 28) using the Climate of Healthy Interactions for Learning & Development (CHILD) tool (Reyes & Gilliam, 2017) and semi-structured interviews (n = 30). Regression analyses revealed a significant relationship between the intervention and classroom climate in two domains, directions and rules and equity. Interview data supported these findings and provided further evidence of changes in teacher attitudes and behaviors. We conclude that teachers who received the IECMHC model showed improved ability to establish certain aspects of healthy social and emotional classroom climates. We also recommend further study of this model using matched-comparison group designs and direct observations of teacher practice. (author abstract)