Although federal regulations require the presence of at least one nonaffiliated member on the roster of an institutional review board (IRB), little research exists about how to foster their participation and satisfaction. Guided by principles of justice and diversity, the Kaiser Permanente Southern California IRB adapted the sociological concept of "cultural capital" to develop training and support with its nonaffiliated IRB members. Using in-depth qualitative interviews with four past and current nonaffiliated IRB members, we describe how our initial and ongoing activities enhanced their ability to analyze, communicate, and complete the ethical review of research. This case study is situated in the gaps of existing research about nonaffiliated IRB members by providing insights into how to sustain their engagement while protecting the rights of research volunteers, particularly from vulnerable communities.