Background Booster seats reduce mortality and morbidity for young children in car crashes, but use is low, particularly in rural areas. This study targeted rural communities in 4 states using a community sports‐based approach. Objective The Strike Out Child Passenger Injury (Strike Out) intervention incorporated education about booster seat use in children ages 4‐7 years within instructional baseball programs. We tested the effectiveness of Strike Out in increasing correct restraint use among participating children. Methods Twenty communities with similar demographics from 4 states participated in a nonrandomized, controlled trial. Surveys of restraint use were conducted before and after baseball season. Intervention communities received tailored education and parents had direct consultation on booster seat use. Control communities received only brochures. Results One thousand fourteen preintervention observation surveys for children ages 4‐7 years (Intervention Group [I]: N = 511, Control [C]: N = 503) and 761 postintervention surveys (I: N = 409, C: N = 352) were obtained. For 3 of 4 states, the intervention resulted in increases in recommended child restraint use (Alabama +15.5%, Arkansas +16.1%, Illinois +11.0%). Communities in 1 state (Indiana) did not have a positive response (–9.2%). Overall, unadjusted restraint use increased 10.2% in intervention and 1.7% in control communities (P = .02). After adjustment for each state in the study, booster seat use was increased in intervention communities (Cochran‐Mantel‐Haenszel odds ratio 1.56, 95% confidence interval [1.16‐2.10]). Conclusions A tailored intervention using baseball programs increased appropriate restraint use among targeted rural children overall and in 3 of 4 states studied. Such interventions hold promise for expansion into other sports and populations.