Background: Stress inoculation training (SIT) interventions have demonstrated promise within military contexts for human performance enhancement and psychological health applications. However, lack of manualized guidance on core content selection, delivery, and measurement processes has limited their use. Purpose: The purpose of this study was to develop and evaluate a comprehensive SIT intervention protocol to enhance the performance and health of military personnel engaged in special warfare and first-response activities. Methods: Multidisciplinary teams of subject matter experts (n = 19) were consulted in protocol generation. The performance improvement/human performance technology (HPT) model was used in the selection, refinement, and measurement of core skills. The protocol was trialed and refined (44 cohorts, n = =300; 2013-2020) to generate the results. Results: Four primary aims were achieved: (1) The generation of a flexible, evidence-based/evidence-driven psychological performance and health sustainment hybrid, SIT-NORCAL. (2) Manualized content and process guidance. (3) The creation of multimedia materials using evidence-based methodologies. (4) The design of initial measurement systems. Preliminary quality improvement analysis demonstrated positive results using standard-of-care and performance enhancement assessments. Conclusion: Hybridized human performance and psychological health sustainment protocols represent a paradigm shift in the delivery of psychological performance training with the potential to overcome barriers to success in traditional care. Further study is needed to determine the effectiveness and reach of SIT-NORCAL.