Background: The success of a facilitator-based model for advance care planning (ACP) in LaCrosse, Wisconsin, has inspired health systems to aim for widespread documentation of advance directives, but limited resources impair efforts to replicate this model. One promising strategy is the development of interactive, Internet-based tools that might increase access to individualized ACP at minimal cost. However, widespread adoption and implementation of Internet-based ACP efforts has yet to be described. Objective: We describe our early experiences in building a systematic, population-based ACP initiative focused on health system-wide deployment of an Internet-based tool as an adjunct to a facilitator-based model. Methods: With the sponsorship of our healthcare system's population health leadership, we engaged a diverse group of clinical stakeholders as champions to design an Internet-based ACP tool and facilitate local practice change. We describe how we simultaneously began to train clinicians in ACP conversations, engage patients and health system employees in thinking about ACP, redesign clinic workflows to accommodate ACP discussions, and integrate the Internet-based tool into the electronic medical record (EMR). Results: Over 18 months, our project engaged two subspecialty clinics in a systematic ACP process and began work with a large primary care practice with a large Medicare Accountable Care Organization at-risk population. Overall, 807 people registered at the Internet site and 85% completed ACPs. Conclusion: We learned that changing culture and systems to promote ACP requires a comprehensive vision with simultaneous, interconnected strategies targeting patient education, clinician training, EMR documentation, and community awareness.