To maximize impact across the broad spectrum of mental health needs exhibited by youth in school settings, interventions must be designed to be effective and efficient and demonstrate good fit with the educational context. The current paper reports on the second phase of an iterative development process for a short-term ''Tier 2'' intervention for use by school-based mental health providers--the Brief Intervention for School Clinicians (BRISC)--using mixed qualitative and quantitative analyses to evaluate feasibility, acceptability, and appropriateness while emphasizing student experiences. This phase was intended to yield information to drive further protocol refinement and testing across subsequent phases. We describe the rationale for, development of, and formative testing of the BRISC intervention. Results suggest that BRISC may be feasible to deliver, acceptable to students, and appropriate to the school context. In particular, the BRISC process appears to be effective in enhancing student engagement in the intervention and identifying and addressing individualized student needs. These findings and directions for further enhancing BRISC's potential for positive impact highlight how treatment development may benefit from initial, small-scale evaluations focused on both client and implementation outcomes.