© 2015 American Cancer Society. BACKGROUND The number of older cancer survivors is increasing as more adults survive to older ages. The objectives of this study were to examine trajectories of physical activity (PA) and physical function (PF) over a 2-year lifestyle counseling study and to identify characteristics of the trajectory groups. METHODS This was a secondary analysis of Reach Out to Enhance Wellness, a randomized controlled trial of home-based lifestyle counseling. The 641 participants were older (≥65 years), overweight (body mass index [BMI], 25 to <40 kg/m2), long-term community-dwelling survivors (>5 years) of breast, prostate, and colorectal cancer from Canada, the United Kingdom, and the United States (21 states) who had been randomly assigned to an immediate intervention or a 12-month-wait-listed control arm. The main outcome measures were PA and PF trajectory group membership. RESULTS Three PA groups and 5 PF trajectory groups were observed. The baseline BMI (P <.001) and self-efficacy for performing strength (P <.0001) and endurance exercises (P <.0002) were the strongest predictors of achieving the highest amount of PA and the most favorable functional trajectory over 2 years. Individuals with low baseline self-efficacy, no PA, and a Short Form 36 PF subscale score < 65 did not benefit from the intervention. CONCLUSIONS This study identified characteristics of survivors who benefited from home-based interventions and suggested alternative approaches for survivors requiring more structured and intensive interventions to promote behavioral changes. Cancer 2015;121:4433-40.