An integrated system of health care for serving the uninsured population of one community was followed from formation through early growth. Funding was provided through the Health Resources Services Administration's Community Access Program to bring together a diverse set of health care providers to form a collaborative network managed by a central administrative entity. Legitimacy building was critical for explaining how the network evolved and the effectiveness of the network in sustaining itself and building a patient base. Based on the study's results, conclusions are drawn that contribute to theory on network legitimacy in health care. In addition, lessons learned are offered that may help other communities address the health needs of the uninsured through collaborative health care networks.