The Centers for Disease Control and Prevention Assessment Initiative enables state and local health departments to improve their capacity to use data for developing policy and ensuring that needed health services are provided. Using reports and comments submitted by staff from the participating states, lessons learned are summarized for the first funding period of the initiative. Although many activities were common among the participating states, the lessons learned varied for them. From a commitment to the concepts of assessment, policy development, and assurance, a vision for the national mission of public health is provided and the various roles in fulfilling the mission are defined.