The Cooperative Extension System was created in 1914 with the passage of the Smith-Lever Act. The act provided resources to improve access to education by creating this nationwide organization to bring land-grant university research and resources to people where they lived and worked. Cooperative Extension was the first formal nationwide structure created for university–community engagement. Expectations for Extension as an engaged institution have changed over time. Once seen chiefly as a source of private value for program participants in local communities, Extension is now also expected to provide public value for those not directly involved in Extension programs. After 100 years of community engagement efforts, Cooperative Extension has learned lessons about measuring and articulating the value of engagement related to professional development, program development, funding, structure, and organization development. Other engaged institutions will find important implications for their work from Extension’s engagement value lessons.