•Describe the facilitators of interdisciplinary collaboration to coordinate care for older adults living longer with serious illnesses.•Identify and describe the barriers to interdisciplinary collaboration to coordinate care for older adults living longer with serious illnesses.•Describe strategies to promote interdisciplinary communication and collaboration and awareness of primary and secondary palliative care. As a component of advanced illness management, palliative care in the outpatient setting can address the complex care needs of older adults living longer with serious illnesses. Communication and collaboration between primary care and palliative care providers is needed to deliver complex care management and to coordinate care, yet optimal strategies for collaboration are ill defined. This exploratory study revealed insights into the study question: What are the facilitators of and barriers to interdisciplinary interactions to coordinate care? Participants were selected through snowball sampling from large academic and community healthcare systems with established community-based palliative care services. Twenty semi-structured interviews were conducted, including primary care and palliative care providers and their patients and families. Interviews were audio recorded and transcribed verbatim. Participants completed a brief survey regarding their background, education and experience with palliative care. Transcripts and field notes were analyzed using Grounded Theory techniques. Four major themes emerged from the data: (i) role clarity, (ii) feedback and collaboration, (iii) workforce need, and (iv) education. Interdisciplinary collaboration to coordinate care was facilitated by defining roles and responsibilities; frequent in person, email, or EMR communication; and education of primary care providers and patients and families regarding primary and secondary palliative care. Barriers that negatively impacted working relationships among primary care and palliative care providers included poor feedback that prevented a shared understanding of patient’s needs and goals of care. Other contributing factors were non-involvement of primary care providers when specialists referred patients to palliative care, lack of resources, and an unclear concept of community-based palliative care. Data suggest the need for greater attention to processes that promote communication and collaboration as well as strategies to promote a greater awareness of primary and secondary palliative care.