Landlocked Malawi ranks among the world’s least developed countries. The country faces numerous social and health problems such as widespread household poverty and a high rate of HIV/AIDS infections, with severe consequences for children’s psychosocial well-being and school success. These childhood risk factors suggest any educational solution that is going to be effective must be responsive to children exposed to early childhood adversity, and adaptive to instruction in resource-constrained schools. Social and Emotional Learning (SEL) curriculum analyzed in this study can potentially meet those requirements, if implemented effectively. In order to understand critical implementation factors in resource-poor contexts, I examined how educational stakeholders at the policy, school, and family levels perceived and engaged with SEL implementation with a mixed methods study in rural Malawi. I used interview, observation, and survey data collected from 16 policymakers, 432 primary school teachers, and 21 parents in Zomba, Malawi. I analyzed the multi-level, mixed methods data using Bronfenbrenner’s theory of ecological child development as an analytic lens. Qualitatively, I found that policymakers identified high rates of HIV/AIDS and declining levels of childcare support from extend families as contributing substantially to children’s social and emotional challenges in Malawi. In response, they implemented a mandatory SEL curriculum with sex and reproductive health as one component of its vision in primary schools. This policy vision did not fully translate into classroom-level SEL implementation, however. Although teachers recognized its importance and showed the consequently high level of instructional commitment, implementing the national SEL curriculum was culturally challenging due to the inclusion of sex and reproductive health, which was not a subject for public discussions in the Malawian culture. Moreover, the curriculum was instructionally demanding due to the novelty of learning concepts and delivery methods. Yet, there was a lack of professional teacher training in these two areas. In this situation, my quantitative analyses showed that individual teacher commitment alone had little effect on their implementation of SEL as a result. While parents also appreciated the curriculum, they questioned the cultural and age propriety of topics related to sex and reproductive health as well. Nevertheless, through internal collaborations within schools and external support from development partners such as Save the Children, teachers and parents found ways to integrate the SEL curriculum into classroom instructions, school activities, and community-level learning opportunities—for instance, using instructional strategies that were less susceptible to cultural sensitivity, organizing school committees and student clubs to offer SEL support beyond lesson hours, and creating voluntary community groups to give children additional learning opportunities after school. Taken together, the facilitative and hindering implementation factors I identified in this study offer important research and policy implications for effective, sustainable SEL intervention in Malawi and other low-income countries. In addition, they demonstrate the significance of greater partnerships and investments across different levels of the ecology of child development—from the home, school, and community to the broader policy level—for assuring children’s well-being and school success through high quality SEL education. Key words: Education Quality, Social and Emotional Learning, Curriculum Policy, Intervention Implementation, Multilevel Mixed Methods Research, Malawi