Posttraumatic stress disorder (PTSD) is common and undertreated among Veterans Affairs (VA) primary care patients. A brief primary care intervention combining clinician support with a self-management mobile app (Clinician-Supported PTSD Coach, CSPTSD Coach) may improve patient outcomes. This study developed and refined an intervention to provide clinician support to facilitate use of the PTSD Coach app and gathered VA provider and patient qualitative and quantitative feedback on CS-PTSD Coach to investigate preliminary acceptability and implementation barriers/ facilitators. VA primary care providers and mental health leadership (N = 9) completed a survey and interview regarding implementation barriers and facilitators structured according to the Consolidated Framework for Implementation Research (CFIR). Clinicians who delivered CS-PTSD Coach (N = 3) and patients (N = 9) who received it provided feedback on the intervention and implementation process. CS-PTSD Coach has high provider and patient acceptability. Important implementation factors included that CS-PTSD Coach be compatible with the clinics' current practices, have low complexity to implement, be perceived to address patient needs, and have strong support from leadership. Diverse factors related to CS-PTSD Coach delivery facilitate implementation, provide an opportunity to problem-solve barriers, and improve integration of the intervention into primary care.