Ecosystem services (ES) researchers have recognized the important role of urban planning decisions in influencing the quantity and distribution of ES in cities. However, knowledge about ES among planners is still modest, and more research is needed about planners’ experiences with ES. For this qualitative study, interviews and focus groups were conducted with actors with roles in urban planning in three Canadian cities. The aim was to understand participants’ knowledge of ES and how they use it. These early adopters were creative, practical, and politically astute in using ES ideas, rhetoric, and tools to build the case for natural urban ecosystems. ES was used in multiple and intersecting ways for awareness-raising, to justify the protection and restoration of natural ecosystems, to provide direction to plans, and to support and supplement existing planning approaches. The strategic use of ES was notable. As a boundary object, ES helped to bridge perspectives and to integrate policies. The ability of ES to facilitate policy coordination is promising. Further research on the effectiveness of ES to improve urban policy is needed.