Background: Communication challenges in the neonatal intensive care unit include fragmented communication, challenges managing expectations amidst uncertainty, and navigating complex medical information. Social workers are well suited to mitigate these challenges. Objective: In this study, we aimed to characterize the extent and nature of social worker participation in family conferences for critically ill infants. Design: We used a longitudinal observational mixed-methods design, enrolling infants with a neurological condition, their parent(s), and their clinicians. All audio-recorded conferences were transcribed and de-identified. Emergent themes and subthemes were identified using conventional content analysis. Results: We enrolled 40 infants and 61 parents. Sixty-eight conferences were held and audio recorded for 24 infants. Social workers were present for 51 of these conferences (n = 51/68, 75%) across 18 cases (n = 18/24, 75%). We identified four themes, conceptualized as distinct roles played by social workers in family conferences: (1) Translator: social workers served as a communicative bridge between parents and the medical team; (2) Coordinator: social workers simplified logistics and connected parents to community resources, including home health agencies and financial assistance; (3) Expectation manager: social workers provided anticipatory guidance and helped parents conceptualize the remainder of the hospital stay, discharge, and life at home; and (4) Advocate: social workers validated parental values and concerns and provided immediate emotional support. Conclusions: Social workers participated in three-quarters of family conferences for critically ill infants. When they participated, they facilitated communication, coordinated care, managed expectations, and advocated for families. These findings underscore the important, varied, and concurrent roles social workers play in the care of critically ill infants. Future communication and family support interventions should leverage these distinct roles.