Little is known about the effects of physical activity behavior change interventions on health outcomes such as lower extremity dysfunction and SF-36 physical health (predictor of mortality) in breast cancer survivors. Furthermore, effect moderators are rarely reported. Therefore, we report the effects of the 3-month BEAT Cancer physical activity behavior change intervention on global health status and health indicators along with moderators of intervention outcomes. Postprimary treatment breast cancer survivors (n = 222) were randomized to BEAT Cancer or usual care (UC). SF-36, muscle strength, body mass index, lower extremity dysfunction (WOMAC), and life satisfaction were measured at 3 months (M3) and 6 months (M6). At M3, adjusted linear mixed-model analyses demonstrated statistically significant effects of BEAT Cancer versus UC on SF-36 physical health [mean between-group difference (M) = 2.1; 95 % confidence interval (CI) 0.3–3.9; p = 0.023], SF-36 mental health (M = 5.2; CI 2.8–7.6; p < 0.001), and all SF-36 subscores. Intervention benefits occurred for lower extremity physical dysfunction (M = −2.7; CI −5.0 to −0.5; p = 0.018), WOMAC total (M = −3.7; CI −6.7 to −0.6; p = 0.018), and life satisfaction (M = 2.4; CI 0.9–3.9; p = 0.001). Statistically significant effects persisted at M6 for mental health and vitality. Baseline value, income, marital status, cancer treatment, cancer stage, and months since diagnosis moderated one or more outcomes. BEAT Cancer improves SF-36, WOMAC, and life satisfaction outcomes with improvements in vitality and mental well-being continuing 3 months postintervention. Several moderators with potential to guide targeting individuals for optimal intervention benefit warrant further study.