School-based childhood obesity prevention programs have grown in response to reductions in child physical activity (PA), increased sedentariness, poor diet, and soaring child obesity rates. Multiple systematic reviews indicate school-based obesity prevention/treatment interventions are effective, yet few studies have examined the school nurse role in obesity interventions. Building on a previous study, this study examines a refined health messaging (Let's Go 5-2-1-0) program delivered to fourth and fifth graders (n = 72) by a school nurse with reinforcement on-site health coaching by senior nursing students. Two nursing schools and two elementary schools participated. Measures of PA, body mass index percentile, and self-reported health habits were collected at baseline (School A, September 2009 and School B, January 2010) and end of year (April 2010 for both schools). Findings included statistically significant increases in PA levels and improvements in child-reported health habits. School nurses can influence obesity prevention. Further research on adoption of school nurse--led obesity interventions is warranted.