Play is an important component of a child's development and learning. Research studies on play therapy have shown the benefits it has on developmental areas such as behavior control, assertiveness, task orientation, and social skills. Primary Project is a school-based play intervention which has consistently shown improved social and emotional skills for children who participated in it. This present study examined the area's most often reported by teachers as At-Risk for the children who engaged in Primary Project. Additionally, it examined the intervention's effectiveness for each of the four domains assessed on the "Teacher-Child Rating Scale (T-CRS) 2.1." There were 307 pre- and post-test T-CRS forms between the years of 2009- 2019 that were analyzed using descriptive statistics and paired sample t-tests. The results indicated that students who were identified and participated in this program often had behavior control issues in the classroom. Additionally, it was found that there was a significant increase in post-test scores after students engaged in the intervention. The clinical implications of this study continued to show support for Primary Project as a school-based intervention for early elementary school students. It also indicated how important play is not only to support mental health problems, but also enhancing a child's way of learning. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]