The problem in the study was that at-risk elementary school students had too many classroom disruptive behaviors. The purpose was to investigate the effect a Professional Development Classroom Management Model would have on reducing these students' misbehaviors. The study implemented a classroom management model to improve the classroom management skills of the 11 teachers who worked with the 224 students in the four grade levels. The generic research design was the concurrent mixed methods research design. Descriptive statistics were calculated; the inferential statistical model was the two-sided z test. Findings for research question 1 showed the mean number of discipline referrals decreased by 11 referrals. Findings for research question 2 showed the number of suspensions decreased by 26 suspensions. (Contains 5 tables.)