Previous research includes various conceptualizations of the successful aging process as it relates to adult functioning. Specifically, Rowe and Kahn's (1997) model of successful aging includes: 1) low probability of disease and disease-related disability; 2) high cognitive and physical functional capacity; and 3) active engagement with life. The aforementioned model applies primarily to later adulthood and fails to consider other important components of the successful aging process for adults (i.e., global sleep quality and affective functioning). This project used a lifespan perspective, which included global sleep quality and affective functioning, to expand on Rowe and Kahn's (1997) model of successful aging and to better understand successful aging across adulthood. To address these objectives, interrelationships between global cognition, global sleep quality, and affective functioning were examined within a nationally representative sample of community-dwelling adults (ages 34 to 84) from the Midlife in the United States Study-II (MIDUS-II). A secondary data analysis was performed using wave two data from MIDUS-II's Cognitive and Biomarker Projects. The Positive Affect Scale, Negative Affect Scale, Pittsburgh Sleep Quality Inventory, and Brief Test of Adult Cognition by Telephone were used to measure this project's constructs of interest. A General Linear Modeling approach (i.e., ANOVA) was used for data analyses, and age was examined as a moderating variable. The results of the primary analyses suggest that when younger adults were compared to older adults: 1) age did not moderate the positive affect-global cognition association, [F(1, 927)=0.22, p=0.64]; 2) the positive affect-global sleep quality association, [F(1, 927)=1.95, p=0.16]; 3) the negative affect-global sleep quality association, [F(1, 928)=2.13, p=0.15]; or 4) the global sleep quality-global cognition association, [F(1, 1042)=3.66, p=0.06]; 5) However, age moderated the negative affect-global cognition association, [F(1, 928)=5.85, p=0.02]. Exploratory analyses indicated that education level moderated the positive affect-global sleep quality association, [F(10, 906)=3.32, p<0.001], as did self-evaluated health status, [F(4, 918)=2.43, p=0.05], and self-evaluated physical health status, [F(4, 921)=3.60, p=0.01]. Self-evaluated physical health status moderated the global sleep quality-global cognition association, [F(4, 925)=2.73, p=0.03]. Results suggest that future research in this area may be warranted to help enhance understanding of the successful aging process across adulthood.