BACKGROUND:Accountable care organizations (ACOs) have increased their use of patient activation and engagement strategies, but it is unknown whether they achieve better outcomes for patients with comorbid chronic physical and mental health conditions. OBJECTIVES:To assess the extent to which practices with patient-centered cultures, greater shared decision-making strategies, and better coordination among team members have better patient-reported outcomes (PROs) for patients with diabetes and/or cardiovascular and comorbid mental health diagnoses. RESEARCH DESIGN:Sixteen practices randomly selected from top and bottom quartiles of a 39-item patient activation/engagement implementation survey of primary care team members (n=411) to assess patient-centered culture, shared decision-making, and relational coordination among team members. These data were linked to survey data on patient engagement and on emotional, physical, and social patient-reported health outcomes. SUBJECTS:Adult patients (n=606) with diabetes, cardiovascular, and comorbid mental health conditions who had at least 1 visit at participating primary care practices of 2 ACOs. MEASURES:Depression/anxiety, physical functioning, social functioning; patient-centered culture, patient activation/engagement implementation, relational coordination. RESULTS:Patients receiving care from practices with high patient-centered cultures reported better physical functioning (0.025) and borderline better emotional functioning (0.059) compared with less patient-centered practices. More activated patients reported better PROs, with higher activation levels partially mediating the relationship of patient-centered culture and better PROs. CONCLUSIONS:ACO patients with comorbid physical and mental health diagnoses report better physical functioning when practices have patient-centered cultures. More activated/engaged patients report better patient emotional, physical, and social health outcomes.