OBJECTIVES: Family members commonly make medical decision for patients with chronic critical illness. This study examines how family members approach this decision-making role in real time. DESIGN: Qualitative analysis of interviews with family members in the intervention arm of a randomized controlled communication trial. SETTINGS: Medical ICUs at four U.S. hospitals. PARTICIPANTS: Family members of patients with chronic critical illness (adults mechanically ventilated for ≥ 7 d and expected to remain ventilated and survive for ≥ 72 hr) who participated in the active arm of a communication intervention study. INTERVENTIONS: Family members participated in at least two content-guided, informational, and emotional support meetings led by a palliative care physician and nurse practitioner. MEASUREMENTS AND MAIN RESULTS: Grounded theory was used for qualitative analysis of 66 audio recordings of meetings with 51 family members. Family members perceived their role in four main ways: voice of the patient, advocate for the patient, advocate for others, and advocate for oneself. Their decision-making was characterized by balancing goals, sharing their role, keeping perspective, remembering previous experiences, finding sources of strength, and coping with various burdens. CONCLUSIONS: Family members take a multifaceted approach as they participate in decision-making. Understanding how surrogates perceive and act in their roles may facilitate shared decision-making among clinicians and families during critical care.