Online communities promote social connection and can be used for formal peer support and crisis intervention. Although some communities have programs to support their members' mental health, few programs have been formally evaluated. The authors present findings from a mixed-methods evaluation of the Stack Up Overwatch Program (StOP), a digital peer support intervention delivered in an online gaming community. Data were collected from members of the Stack Up Discord server between June and October 2020 and included chat messages, survey responses, encounter forms (documenting information from private interactions between users and peer supporters), and interviews with peer support team members. The authors analyzed data on demographic characteristics, mental health and crises, use of and experiences with StOP, and chat posts. Thematic analysis and descriptive statistics were combined in a joint display table, with mixed-methods findings explained in narrative form. The findings show that StOP provides users in crisis with a source of mental health support when other options have been exhausted and that military and veteran users valued the connections and friendships they formed while using it. Participants reported that StOP met needs for support and connection when formal services were inaccessible or did not meet their needs, and volunteer peer supporters detailed how StOP's design facilitates use of the intervention. Volunteering offered members of the peer support team a "family feeling" facilitated by the unique chat room structure. Community-based crisis prevention programs administered through chat rooms may provide valuable support to both users and peer support providers.