Background. This study tested the initial efficacy of implementing a physical activity (PA) behavior change intervention for midlife African American (AA) men. Methods. Intervention components were based on information gathered during formative research preceding the intervention. Eligible participants were underactive AA men ages 45–66 years. In a quasi-experimental pre–post design, participants attended 90-min program sessions twice weekly for 8 weeks. Session topics specific to PA included overcoming barriers, gaining social support, setting goals, tracking progress and integrating into one’s lifestyle. Participants were assigned to teams to facilitate group discussion, problem solving, accountability and camaraderie. Results. 25 AA men (mean age = 54.7 ± 4.8 years) completed the intervention. After 8 weeks, significant (P < 0.05) positive changes were observed for moderate to vigorous-intensity PA (+7.3 hour week⁻¹) and overall PA (+9.4 hour week⁻¹), self-efficacy for PA (+12%), social support for PA from family (+28%) and friends (+53%), self-regulation for planning (+33%) and goal setting (+48%) and each fitness component (+9 to +144%). Based on a post-intervention satisfaction survey, participants rated the program very positively. Conclusion. These positive results attest to the feasibility of successfully engaging midlife AA men in a tailored PA behavior change program.