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. We launched a 24-clinic site cluster randomized clinical trial in July 2022 comparing two SCC delivery approaches: a team-based intervention in which patients engage in advanced care planning and symptom assessments with a lay health worker 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 implementation and effectiveness of these SCC delivery approaches. Methods: We invited study staff at all 24 sites, including community oncology clinics, Kaiser Permanente clinics, Veterans Affairs facilities, safety-net hospitals, and academic centers, to participate 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, readiness, facilitators, and barriers to SCC delivery. Surveys were analyzed using descriptive statistics; interviews were analyzed using thematic analysis. Results: Among 30 interview participants across 24 clinics, of which 23 completed surveys, 9 (30%) were clinic principal investigators, 11 (36.7%) were research staff, and 10 (33.3%) were implementation staff. Survey respondents implementing team-based SCC were more confident that their approach: 1) accounted for patient care preferences (93.3%) and 2) had strong evidence (86.7%) than respondents implementing technology-based SCC (62.5% and 25.0% respectively). More respondents implementing team-based SCC expressed confidence in organization leadership (100%) and adequate resources for SCC (86.7%) than respondents implementing technology-based SCC (75.0%). Among interview participants, team-based approaches for SCC delivery were considered more effective, as they could: 1) reduce time burden for clinicians 2) tailor delivery to patient preferences; and 3) increase patient support. Participants believed that team-based approaches would also be more difficult and costly to implement. Barriers to both SCC delivery approaches include: a) limited technology access for patients, b) competing organization priorities which limit staffing and funding for SCC, and c) information overload for patients and caregivers. Conclusions: Implementation of SCC delivery approaches is needed but requires organizational leadership and implementation resources. Team-based approaches are considered more effective, but barriers such as staffing and funding may inhibit the scalability. Implementation evaluations are crucial to understand real-world applicability and scalability of SCC delivery.