To support conservation practices, societal demand for understanding fundamental coastal ocean ecosystem mechanisms has grown in recent decades. Globally, these regions are among the world’s most productive, but they are highly vulnerable to extractive and non-extractive stresses. In 1999, we established the Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO) to perform basic and use-inspired, long-term ecological research at local to large marine ecosystem (LME) scales. Coordinated investigations of ecosystem patterns and dynamics focused on nearshore coastal waters and hard-bottom habitats (rocky intertidal and kelp forests) in the California Current Large Marine Ecosystem. Communicating relevant scientific discoveries to inform decision-making was an integral component, as was commitment to training new generations of interdisciplinary marine scientists, thereby building scientific capacity and expertise in marine conservation science and policy. Issues of climate change and ocean acidification, wildlife disease outbreaks, oil spills, and conservation strategies such as marine protected areas have spotlighted the immense value of long-term monitoring and research at the LME scale. Here, we reflect on PISCO’s approach and progress in linking science, conservation, management, and policy using 20 years of experience in the formation and operation of this research network.