Mental health concerns are on the rise among youth, contributing to a growing need for school-based mental health services. However, challenges to service provision arise due, in part, to workforce shortages, service fragmentation, and inefficient allocation of staff time. The current study describes the professional competencies and time allocation of four school-based mental health professions (i.e., school counselors, school psychologists, school social workers, and school nurses) in order to demonstrate how schools can leverage the skills of their existing staff to coordinate a comprehensive approach to support student mental health. First, we identified the core clinical competencies needed to implement the key features of comprehensive school mental health systems. Then, we crosswalked these clinical competencies with the training standards of the four professions. Finally, we conducted a systematic review of the literature to understand how these professionals’ time is allocated, as well as their responsibilities related to the provision of mental health services. Results demonstrated that, although all four professions receive training in most of the core competencies needed to implement comprehensive school mental health services, their skillsets are often underutilized in day-to-day practice. Thus, we concluded that there are at least two untapped opportunities for school leaders to support student mental health—first, maximize the use of school mental health professionals through task-shifting (i.e., reassigning tasks less central to mental health service delivery to other staff), and second, implement an integrated model of school mental health services to efficiently leverage the mental health training of professionals.