The purpose of this proof-of-concept study was to examine the outcomes and acceptability of a spiritual intervention for moral injury led by veteran peers in a Veteran Service Organization (VSO), called "Heroes to Heroes." From baseline to 1-year follow-up, 101 veterans who participated in the intervention completed the evaluation surveys at four time points assessing psychological outcomes (moral injury, posttraumatic stress disorder [PTSD] symptoms, and life satisfaction), spiritual outcomes (spiritual struggles and spiritual transcendence), and their perceived helpfulness of the program. In addition, we conducted four focus groups with six to eight alumni to more fully understand veterans' views and experiences of the program. Focusing on the longitudinal surveys, latent growth modeling analyses revealed veterans generally improved across the psychological and spiritual outcomes in the study. Specifically, veterans reported steady decreases in moral injury outcomes, PTSD symptoms, and spiritual struggles along with increased life satisfaction and spiritual transcendence over the 1-year period. An inductive content analysis of veterans' responses to open-ended items in the surveys and focus group interviews revealed four possible mechanisms or facilitators of these outcomes: (a) social connectivity and belonging (e.g., shared vulnerability and camaraderie); (b) behavioral engagement in core aspects of their spirituality (e.g., sacred practices and visiting sacred places); (c) spiritual transformation and growth (e.g., closeness with God and divine forgiveness); and (d) appreciation for diversity (e.g., religious and military). Overall, these findings affirm the potential effectiveness and acceptability of the VSO's peer-led spiritual intervention for promoting the holistic healing among veterans who are contending with emotional and spiritual wounds of war. (PsycInfo Database Record (c) 2024 APA, all rights reserved).