Background: Advanced care planning and symptom management, otherwise known as Supportive Cancer Care (SCC), are fundamental services that patients should receive after a cancer diagnosis. Yet, barriers prevent such care delivery. In response, we launched a 24-clinic site cluster randomized trial in July 2022 comparing two SCC delivery approaches: a team-based intervention in which patients engage with a SCC-trained health educator via phone versus a technology-based intervention in which patients receive internet-based SCC education. The preliminary aim of this study is to evaluate clinic characteristics that may impact SCC implementation and effectiveness. Methods: Study staff at all 24 sites, including community oncology clinics, Kaiser Permanente clinics, Veterans Affairs facilities, safety-net hospitals, and academic centers, participated in a survey and semi-structured interview. We used Consolidated Framework for Implementation Research (CFIR) and Reach, Effectiveness, Adoption, and Implementation (RE-AIM) frameworks to assess organizational culture, facilitators, and barriers. Surveys were analyzed using descriptive statistics; interviews were qualitatively coded and thematically analyzed. Results: Among 31 interview participants, of which 24 completed surveys, 9 (29%) were principal investigators, 10 (32.3%) were research staff, and 12 (38.7%) were implementation staff. Survey respondents implementing team-based SCC were more confident that their approach accounted for patient care preferences (93.8%) and had strong evidence (87.5%) than respondents implementing technology-based SCC (62.5% and 25.0% respectively). More team-based SCC respondents expressed confidence in organization leadership (100%) and adequate resources for SCC (87.5%) than technology-based SCC respondents (87.5% and 75.0% respectively). Interviews revealed that team-based SCC was more likely to be effective, as it could 1) adapt delivery to patient needs, 2) improve patient support and outcomes, and 3) decrease clinician time burden, rather than tech-based SCC which could 1) worsen sociodemographic disparities in SCC delivery due to digital delivery and 2) result in EHR messaging overload for patients and clinicians. Participants were concerned about sustainability of both SCC approaches due to 1) competing organization priorities that limit staffing and funding, 2) barriers to technology access for patients, 3) information overload at time of diagnosis, and 4) patients’ hesitancy to engage in end-of-life care discussions. Conclusions: Supportive cancer care requires resources, organizational leadership, and assessment of patient needs. While the comparative effectiveness of team-based and technology-based approaches remains yet to be determined, many believe that team-based approaches may be more effective but remain concerned about sustainability.