BackgroundChild mortality rates during hospitalisation for acute illness and after discharge are unacceptably high in many under-resourced settings. Childhood vulnerability to recurrent illness, and death, is linked to their families’ situations and ability to make choices and act (their agency). We examined vulnerability and agency across treatment-seeking journeys for acutely ill children and considered the implications for policy and practice.MethodA qualitative sub-study was embedded within the prospective CHAIN Network cohort study, which is investigating mechanisms of inpatient and post-hospital discharge mortality among acutely ill young children across a spectrum of nutritional status. Primary data were collected from household members of 20 purposively selected cohort children over 18 months through formal interviews (total n = 74), complemented by informal discussions and observations. Data were analysed using narrative and thematic approaches.ResultsTreatment-seeking pathways were often long and complex, particularly for children diagnosed as severely malnourished. Family members’ stories reveal that children’s carers, usually mothers, navigate diverse challenges related to intersecting vulnerabilities at individual, household and facility levels. Specific challenges include the costs of treatment-seeking, confusing and conflicting messaging on appropriate care and nutrition, and poor continuity of care. Strong power inequities were observed between family members and health staff, with many mothers feeling blamed for their child’s condition. Caregivers’ agency, as demonstrated in decision-making and actions, often drew on the social support of others but was significantly constrained by their situation and broader structural drivers.ConclusionTo support children’s care and recovery, health systems must be more responsive to the needs of families facing multiple and interacting vulnerabilities. Reducing incurred treatment costs, improving interpersonal quality of care, and strengthening continuity of care across facilities is essential. Promising interventions need to be co-designed with community representatives and health providers and carefully tested for unintended negative consequences and potential for sustainable scale-up.