Operating from intersecting theories of validation, marginality, and mattering, this phenomenological study investigated undocumented student support services from the perspective of 49 Undocumented Student Resource Center (USRC) practitioners. In-depth interviews highlighted the ways that USRC practitioners served as validating agents, directly transmitting or negotiating the transmission of institutional resources and services for undocumented students. USRC practitioners engaged in complex multisector work; relatability, validation, and empowerment strategies; and holistic approaches toward student support. Their narratives evidence best practices in undocumented student support services and contribute to the generation of practice-related opportunities across higher education institutions. This study raises implications for higher education research and practice.