The Centers for Disease Control and Prevention (CDC) created the Career Epidemiology Field Officer (CEFO) Program in 2002 to strengthen state and local epidemiology capacity for public health preparedness and response. CEFOs are CDC epidemiologists, assigned by request, to state and local public health departments to fill critical gaps in state and local needs. CEFOs work and have an impact in many areas of public health including surveillance, epidemiology, preparedness, workforce development, policy development, partnership building, and technical assistance. Although the CEFO Program has operated for over a decade, minimal evaluation has conducted to assess barriers, successes, and impact of program capacity building efforts in the states. To gain a broader understanding of the work conducted by CEFOs, an evaluation of the CEFO Program’s contributions in Idaho, Montana, and Wyoming, was conducted using the CDC Program Evaluation Framework. Program evaluation is an important tool to understand the impact of a program, identify barriers to success, and to highlight best practices. Lessons learned from this evaluation will help strengthen the CEFO assignment, bridge the gap between epidemiology and preparedness, and this evaluation plan could be considered as a model for evaluations of other CDC field assignment programs.