Background: There is a paucity of studies, especially among diverse populations, demonstrating the effects of policy and environmental interventions to increase regular physical activity. The Grow Healthy Together Chattanooga project provided the opportunity to assess the impact of physical activity policy and environmental interventions on the physical activity among predominately African American children living in the inner city. Methods: Using the System for Observing Physical Activity and Recreation in Communities (SOPARC), the authors examined the physical activity of children along urban pedestrian/bike routes/trails and recreational park areas within the boundaries of the Grow Healthy Together Chattanooga communities. SOPARC data were collected at baseline (fall 2010/spring 2011) and repeated (spring 2014) in each community. Results: The SOPARC assessments yielded a total of 692 child/youth observations in 2010 and 806 observations in 2014. Children/youth observed in 2014 were greater than 2 times the odds of engaging in moderate/vigorous physical activity compared with their 2010 counterparts (odds ratio = 2.75, 95% confidence interval, 1.43–5.32). Conclusions: The present findings support the hypothesis that policy and environmental interventions can contribute to increased physical activity levels among children/youth over ∼3-year period. These results provide evidence that improved access to “urban” pedestrian/bicycle routes/trails appears to translate into increased opportunities for physical activity among inner city children/youth.