Explorations of workflow development within primary care allow us to understand initial steps in the pace of knowledge and practice acclimatization within clinics. This study describes use of practice facilitation as an implementation strategy to communicate shared project goals and monitor and support refinement of practice behavior. This study engaged eight health care organizations, including 55 primary care practices, ≈380 clinicians, and ≈620 nursing and support staff in a guideline implementation project regarding United States Preventive Services Task Force use of aspirin recommendations for primary prevention of cardiovascular events.