During its 20-year history, the King County Asthma Program (KCAP) at Public Health—Seattle & King County has pioneered research and programs in asthma management. Under the guidance of Dr. Jim Krieger, KCAP developed its core programming: home visits with community health workers (CHWs) to reduce asthma triggers in homes and improve asthma outcomes. For 20 years, KCAP’s projects and research have helped build the solid evidence base for this model, which now informs asthma services offered across the nation. To build this program, KCAP program staff have worked with care providers in public health settings, hospital systems, community clinics, health plans, academic institutions, schools, housing agencies and community organizations. Since its original demonstration project began in 1997, KCAP has engaged more than 4,000 patients in programs to manage environmental asthma triggers and improve care delivery for better health outcomes. These efforts have contributed to decreases in asthma-related hospitalizations and urgent care use, increases in patient and caregiver quality of life, and a greater overall return on investment when compared to standard care. KCAP continues to build the evidence base for the CHW model and patient-centered asthma care, and it serves as an exemplar for asthma care delivery across Washington state and nationwide.