Brazilians are a rapidly growing ethnic immigrant population in the United States (U.S.), and there is a lack of childhood obesity prevention interventions addressing the needs of Brazilian preschool-age children. Using the family ecological model (FEM) as a guide, this developmental cross-sectional study assessed the preferences (content, intervention modality, and language) of 52 individual Brazilian immigrant parents (27 mothers, 25 fathers) for a family-based intervention to promote healthful energy balance-related behaviors (EBRB). Overall, 85% or more of parents reported being interested or very interested in content related to five of the seven assessed EBRBs (increasing fruits and vegetables, reducing unhealthy foods and sugar-sweetened beverages, increasing physical activity, and reducing screen time). Parent-preferred intervention modalities were group sessions delivered by community health workers (CHWs, 86.5%), email (84.6%), and messaging (78.8%), with most parents (71.2%) indicating a preference for content in Portuguese. Interventions integrating multiple components, such as group sessions offered by CHWs and text messaging using SMS and WhatsApp, should be considered. Future steps for intervention development should include investigating different communication channels and their integration into a culturally and linguistically tailored family-based intervention designed to promote healthful EBRBs of preschool-age children in Brazilian families living in the U.S.