Law enforcement agencies are often first responders for people experiencing mental health or substance use crises because most communities have few other options. Many communities are exploring alternative crisis-response strategies to better connect people in crisis to the services they need. One alternative model in Denver, Colorado, called the Support Team Alternative Response (STAR) program allows teams of clinicians and medics to respond to crises without police involvement. To date, not much research has been done to understand the implementation and impact of non-police response models. Denver has committed to a robust evaluation of the STAR program implementation, outcomes, and costs. This brief outlines the methods and key findings from the first year of a two-year mixed-methods evaluation of the STAR program, including recommendations and next steps as the evaluation enters its second year. It focuses on understanding program implementation, including successes and challenges, and on informing practitioners and policymakers who are seeking to implement and improve similar programs.