Positive mental health is an essential aspect of development from childhood through adulthood. Mental health includes emotional, psychological, and social well-being. It influences cognition, feelings, and behaviors. Mental health wellness determines how an individual responds to stress, engages with interpersonal relationships, and makes healthy choices. School systems often prioritize these important areas of development in education and are called to be a conduit to providing mental health supports and services for students. School-aged children and adolescents often experience mental health struggles and challenges that impact their ability to access and participate fully in learning. The COVID-19 pandemic has exacerbated these challenges and intensified the calling for schools to provide school-based mental health services in educational environments. There is a palpable need for schools to leverage their systems to increase evidence-based mental health services to support these unmet needs. This study involved the engagement and participation of team members from the student support services teams across three elementary schools in the district. Through a professional development offering, team members were introduced to an evidence-based model for assessing and implementing comprehensive school mental systems. The study included the use of the National School Mental Health Curriculum and School Mental Health Quality Assessment-School as evidence-based improvement planning tools. The focus of the study was to improve team members' understanding of comprehensive school mental health best practices and to develop capacity to lead school mental health improvement efforts in the district. Overall, the study evaluated an intervention to determine its function and contribution to preparing school teams to lead school mental health systems improvement efforts. Data analysis illustrated the participants' experience in engaging in the professional development offering and helped guide improvement for implementation of professional development. The study's recommendations were designed to inform local district planning efforts and to suggest implications for practice at the state and federal level. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]