A more complete conceptual model of the social determinants of health (SDOH) screening and referral process is needed to identify effective interventions to address unmet social needs that impact health outcomes. The objective was to develop an evidence-based, complex, multi-factorial model that makes explicit the behaviors and experiences of both patients and the care team (factors) who use an SDOH platform to facilitate patient connections to community resources. The resulting model organized 88 factors among five main stages in the process and among health outcomes. Factors were grouped into eight categories among person, system, and organization levels. Most factors were related to the screening process, with sparse factors related to referral completion. The resulting model is offered as an initial step toward the development of a simulation model to assess interventions before implementation in real-world settings.