Background. Performance-based measures of physical performance are examined for an older cohort of relatively high-functioning men and women. The influences of baseline behavioral, social, and psychological characteristics on patterns of change in performance over 2.5 years are examined. Methods. A cohort of relatively high-functioning men and women, aged 70–79, identified in 1988 by subsampling from three community-based studies on the basis of physical and cognitive function. Baseline assessments included physical performance, sociodemographic characteristics, health status, and behavioral, social, and psychological characteristics. A summary measure of physical performance was developed from tests of balance, gait, lower body strength and coordination, and manual dexterity. In-home assessments were repeated at follow-up in 1991. Results. Linear regression models were used to identify significant behavioral, social, and psychological predictors of better performance at follow-up, controlling for known sociodemographic and health status predictors. Significant, independent associations with better performance were found for participation in moderate and/or strenuous exercise activity and greater frequency of emotional support from social networks, particularly among those reporting low frequency of instrumental support. These effects remained significant independent of incident health conditions during follow-up. None of the psychological characteristics was a significant predictor. Conclusions. Maintenance of better physical performance within a high-functioning cohort is influenced by prior exercise behavior and social network emotional support. Observed patterns of both decline and improvement in performance suggest that older age is not uniformly associated with declines. Predictors of better performance identified here may offer potential for effective interventions to promote more successful aging.