Integrated behavioral health care (IBHC) models in primary care are positioned to address the unmet needs of traditional behavioral health models. However, research support is limited to specific populations, settings, and behavioral health conditions. Empirical evidence is lacking for expansion to larger health systems and diverse behavioral health conditions. This study examines perspectives on IBHC implementation in a large medical center. Semi-structured interviews were conducted with 24 health providers and administrators in two primary care clinics with IBHC. Thematic analysis demonstrated that participants had an overall favorable perception of IBHC, but also perceived implementation challenges, including difficulties with access, underutilization, team dynamics, and financial and interdepartmental issues. The findings suggest that IBHC implementation barriers in existing large health systems risk diminishing potential benefits and successful adoption. These barriers can be combated by incorporating systems change strategies into implementation frameworks, with a focus on barrier prevention and detection and long-term sustainability.