This case study uses a hospital family safety reporting intervention, coproduced with key partners, with the aim to garner lessons for developing complex, hospital-based interventions. Health equity, communication science, health literacy, and organizational behavior principles were utilized to develop a family safety reporting intervention consisting of a family safety reporting tool, staff and family education, and a process for reviewing and sharing family reports with unit and hospital leaders. We evaluated intervention training rates and hospital impact (comparing family-reported safety incidents received by the hospital through voluntary incident reports at baseline to incidents received through voluntary incident reports and after the intervention). Additionally, we analyzed field notes and minutes to describe lessons learned from applying these principles in complex, hospital-based interventions. We trained 208 families, 149 nurses, 42 resident physicians, and 7 attending physicians in the intervention. After implementing the intervention, the frequency of families from whom the hospital documented safety concerns increased from an average of 0.4 per month at baseline to 4.4 per month after the intervention. Four key lessons emerged: (1) Build deep and regular partnerships across all intervention key partners, including initial skeptics. (2) Tailor the intervention message to each audience. (3) Embrace flexibility and a growth mindset when weighing suggestions and adapting interventions. (4) Equity is an investment, not a checkbox. We conclude that health equity, communication science, health literacy, and organizational behavior can inform inclusive, effective, complex hospital-based interventions but require deep partnerships, tailored messaging, flexibility, a growth mindset, and a commitment to equity.