Abstract Background The prevalence of household violence in low- and middle-income countries (LMICs) is high, and exposure to violence has significant adverse effects on both mental health and child development across generations. Evidence-based services to improve parenting practices and reduce household violence in LMICs are scarce, particularly across rural regions of West Africa. This study explored the feasibility, acceptability, and potential benefits of an evidence-based home-visiting intervention to promote early childhood development and reduce household violence—the Family Strengthening Intervention for Early Childhood Development and Violence-Prevention (FSI-ECD + VP)—among vulnerable families in rural regions of Sierra Leone. Methods Eighty dual-caregiver households in the Makeni region of Sierra Leone were included in the study (N = 160 caregivers; 73% female). Eligibility criteria included having at least one child aged 6–36 months and elevated scores (> 62.5) on the Difficulties in Emotion Regulation Scale (DERS). Community Health Workers (CHWs) employed in the Makeni region completed a 3-week FSI-ECD + VP training. Families were randomized to receive either the FSI-ECD + VP or treatment as usual (TAU). Research assistants blinded to treatment assignment assessed caregiver mental health, caregiver-child interactions, and household violence at baseline, post-intervention, and 3-month follow-up time points. Results Triangulation of quantitative and qualitative data showed that caregivers, CHWs, and supervisors generally perceived the intervention as beneficial, feasible, and acceptable. Mixed effects models showed that caregivers who received the FSI-ECD + VP had significantly improved caregiver-child relationship outcomes compared to TAU as assessed by the Home Observation for Measurement of the Environment and the Observation of Caregiver-Child Interactions at post-intervention. Preliminary data also suggests that caregivers receiving the FSI-ECD + VP were less likely to have experienced intimate partner physical violence during the post-intervention period, and had lower symptoms of anxiety and depression at 3-month follow-up. Conclusions FSI-ECD + VP delivery by CHWs in Sierra Leone may be feasible and acceptable; it may also help improve caregiver-child interactions and reduce the likelihood of household violence among vulnerable families with young children. Task-sharing approaches may help increase acceptability and access to evidence-based behavioral interventions that promote early childhood development and violence prevention among families in rural regions of Sierra Leone and other similar settings. Trial registration The study is registered in clinicaltrials.gov (NCT 03045640; 07/22/2020). This study follows the Consort 2010 guidelines for reporting of clinical trials.