As the US population ages, communities must adapt to help older adults thrive. Built environment features, like safe sidewalks, provide the foundation for age- and physical activity-friendly communities. The Senior Change Makers Pilot Study tested an eight-week intergenerational program that taught seniors and college students to perform audits of their pedestrian environments, identify barriers, and advocate for improvements. Four low-income senior housing sites in San Diego, CA were randomly assigned to an advocacy program or physical activity control (n = 50 seniors; n = 20 students). A mixed methods evaluation used pre-post surveys, focus groups, and direct observation. The primary outcome was changes in seniors' advocacy confidence and skills. Other outcomes included advocacy actions and outcomes, changes in intergenerational attitudes, study feasibility, and physical activity measured via accelerometer. Main analyses were conducted using repeated measures ANOVAs to examine time by condition interactions. Results showed that seniors in the advocacy condition increased their advocacy outcome efficacy (p = .03) and knowledge of resources (p = .04) more than seniors in the physical activity condition. Almost all seniors in the advocacy condition completed an audit of nearby streets, made an advocacy presentation, and submitted an online advocacy request. Immediate results included repairs to three crosswalks, a sidewalk, and a water meter box. The City approved requests for additional lighting, curb cuts, and crosswalk markings. Seniors in the advocacy condition improved their attitudes about younger adults (p = .02). Students in both conditions reported increased respect for older adults and desire for future intergenerational work. Students in the physical activity condition decreased ageism (p = .02). Seniors' accelerometer-measured physical activity did not significantly increase, but self-reported transportation activity increased in the physical activity condition (p = .04). Students in the physical activity condition decreased sedentary behavior (p = .05). Process evaluation showed feasibility of recruitment, 89% attendance rate, and intervention fidelity and quality. This pilot study showed the potential of intergenerational advocacy to empower participants and make communities more age- and activity-friendly. Longer studies are needed to undertake larger advocacy projects and quantitatively assess environmental changes and health benefits.