<p>To investigate the link between HbA1c, a marker of glucose control, and positive emotional well-being (PEWB). Data were from a nationwide survey (<i>N</i> = 1933) which included an older, chronically ill subgroup (<i>N</i> = 905). Two aspects of PEWB were assessed via cross-sectional regression analyses predicting HbA1c from positive affect and life satisfaction individually, controlling for demographic variables. HbA1c was analyzed via blood-spot from a finger-prick. The mediating role of health behaviors (smoking, alcohol, BMI, and moderate exercise) were also examined. Higher positive affect and life satisfaction were significantly related to lower HbA1c in the overall and older, chronically ill samples controlling for demographics, as well as health behaviors and depression. Individuals with lower positive affect and lower life satisfaction were at increased odds of having clinically elevated HbA1c (&gt; 6.5), indicative of diabetes, in both the overall sample (OR = 1.37; and OR = 1.13) and the chronically ill, older sample (OR = 1.59; and OR = 1.14). Two health behaviors emerged as mediators in the overall sample: BMI and exercise. These findings suggest that PEWB factors such as positive affect and life satisfaction are associated with HbA1c in both the general population and older, chronically ill individuals. Health factors such as BMI and moderate exercise mediate this relationship.</p>