Our goal was to investigate the sustainability of care practices that are consistent with the collaborative chronic care model (CCM) in nine outpatient mental health teams located within US Department of Veterans Affairs (VA) medical centers, three to four years after the completion of CCM implementation. We conducted qualitative interviews (N = 30) with outpatient mental health staff from each of the nine teams. We based our directed content analysis on the six elements of the CCM. We found variable sustainability of CCM-based care processes across sites. Some care processes, such as delivery of evidence-based psychotherapies (EBPs) and use of measurement-based care (MBC) to guide clinic decision-making, were robustly maintained or even expanded within participating teams. In contrast, other care processes-which had in some cases been developed with considerable effort-had not been sustained. For example, care manager roles were diminished in scope or eliminated completely in response to workload pressures, frontline care needs, or the COVID-19 pandemic. Similarly, processes for engaging Veterans more fully in decision-making had generally been scaled back. Leadership support in the form of adequate team staffing and time to conduct team meetings were seen as crucial for sustaining CCM-consistent care. Given the potential impact of leadership turnover on sustainability in mental health, future efforts to implement CCM-based mental health care should strive to involve multiple leaders in implementation and sustainment efforts, lest one key departure undo years of implementation work. Our results also suggest that implementing CCM processes may best be conceptualized as a partnership across multiple levels of medical center leadership.