Physical activity (PA) helps prevent several diseases; however, individuals residing in low-income neighborhoods have lower PA participation rates due to social disparities, as outlined in the social-ecological model. The purpose of this pilot study was to apply the social-ecological framework to test the effectiveness of a six-month, community-based PA program in a low-income neighborhood. Participants (n = 45) lived in a low-income neighborhood near a community fitness center. Those randomized to the experimental arm (n = 23) received gym access and attended monthly on-site workshops (Months 1-3) designed to enhance PA determinants such as planning and habit formation. The remaining participants (n = 22) were assigned to a wait-listed control group. PA, body composition, and fitness data were collected using accelerometers, BODPOD, and on-site fitness assessments at baseline, Month 3, and Month 6. Compared to the control group, participants in the experimental arm engaged in more moderate-to-vigorous PA (d = 0.48, d = 0.74), total PA (d = 0.41, d = 0.99), and steps (d = 0.48, d = 0.92) at Months 3 and 6, respectively. The experimental group also showed improvements in fitness tests, including the 30-s chair test (d = 0.29, d = 0.23) and the 8-foot up-and-go test at Month 3 (d = -0.23), though these gains were not sustained at Month 6. Overall, this pilot study supports the feasibility of promoting PA and improving fitness outcomes in a low-income neighborhood. Notes for improvement and future directions are provided such as tracking PA exclusively performed at the community center to better assess program impact.