School mobility, compounding socioeconomic inequities, can undermine academic achievement and behavior, particularly during middle school years. This study investigates the effect of a school-based integrated student support intervention – City Connects – on the achievement and behavior of middle school students who experience school mobility. Using administrative data from a large, urban, public school district in the U.S., we apply student fixed effects and event studies methods to analyze the academic and behavioral performance of students changing schools. The results indicate that students who moved to schools implementing the City Connects intervention performed better academically and behaviorally than other students.