The Western Region Public Health Training Center (formally the Arizona Public Health Training Center) conducts competency-based needs assessments and provides workforce development assistance to public health agencies in the U.S. Department of Health and Human Services Region IX. Since its launch in 2012, the Center’s Public Health Essentials in Action Training has evolved. It is now offered in-person and online and has been adapted for rural communities. The evolution of the training, beginning with course planning and development, is described, as well as how factors in the public health workforce influenced the course’s evolution and how the course has been adapted for different platforms and populations. Finally, an overview of evaluation efforts offers insight into course effectiveness for this and other trainings offered by the Western Region Public Health Training Center.