Background: Electronic patient-reported outcome (ePRO)-based symptom management can improve cancer care outcomes. However, implementation is challenging as it requires 1) tremendous technical resources to integrate ePROs into the electronic health record (EHR), 2) substantial buy-in from clinicians and patients, 3) between visit symptom management, and 4) institutional investment to support engagement. Methods: The SIMPRO Consortium developed and deployed eSyM, an EHR-integrated ePRO-based symptom management program for medical oncology and surgery patients, at 6 cancer centers between September 2019-March 2022. Site teams document new and changes to implementation strategies monthly using REDCap (data collection is ongoing). Strategies are itemized using the Expert Recommendations for Implementation Change (ERIC) list and mapped to the Consolidated Framework for Implementation Research (CFIR) list of barriers. The SIMPRO Coordinating Center (Dana-Farber) reviews all ERIC-CFIR classifications for consistency. Results: To date, 162 distinct strategies have been documented. On average, sites have implemented 23 strategies, 5 preparing for go-live and 18 remaining active beyond go-live. Preparation of clinical staff, training, and routine program evaluation are consistent high impact strategies. Other adaptive strategies have varied across sites, including various approaches to patient and provider engagement. Foundational strategies have been deployed by the coordinating center to support the multi-center initiative. Conclusions: Methodical deployment using theory-based implementation strategies may foster adoption of novel health care delivery systems by patients, clinicians, and institutions. Attention to the specific high-value strategies identified by the SIMPRO Consortium could support similar ePRO deployment at other institutions.