This study uses the constellation approach of transition theory as a theoretical framework to depict the ways in which facilitators and barriers in police system's structure, culture, and practice interact to shape police response to persons with mental illnesses (PWMIs). The study utilizes the framework method to analyze 57 in-depth interviews with police officers in Texas. Using a hybrid approach of inductive and deductive thematic analysis, we develop a matrix of four quadrants characterizing the constellation of mental health service provision by police: (1) structural barriers (deficits in resources, unsuccessful collaboration, lack of training), (2) structural facilitators (crisis intervention teams, informal cross-disciplinary collaborations, technology), (3) cultural barriers (role conflict, perceived inability to help, stigma), and (4) cultural facilitators (the police mission ‘to serve and protect’, improving police public image, managerial support). The study ends with recommendations for the scaling up of police mental health service provision to PWMIs.