In order to increase the pace and scale of managing forests to reduce wildfire risk in the western U.S., federal agencies have adopted policies that promote an all lands management (ALM) approach, which extends management actions across jurisdictional boundaries. To better implement such policies, ALM approaches require new governance systems that overcome barriers found in existing systems, which typically address jurisdictions separately. Polycentric governance systems, characterized by multiple and diverse actors at different scales operating in coordination with one another under an overarching set of rules, have emerged to address wildfire risk in multi-ownership landscapes. We describe these polycentric systems using three case studies of US Forest Service-Natural Resources Conservation Service Joint Chiefs Landscape Restoration Partnership projects in Oregon and California. While all three cases demonstrate polycentric systems, we found diversity in terms of partnering organizations and levels of success in implementing wildfire risk reduction projects. Lessons from our research can inform more effective implementation of ALM policies for managing natural resources and processes in multi-jurisdictional landscapes. Our research suggests these systems can be strengthened when: bottom-up and top-down processes and incentives for establishing them converge; actors within the system coordinate effectively; policies enable flexibility and adaptiveness for how systems function in different places; multiple actors at multiple scales are able to supplement one another’s capacity; and legal and policy mechanisms facilitate efficient transfer of funding and resources between actors in the system to accomplish work.