This study explored how depressive symptoms in cardiac patients changed in relation to their performance of health behaviors in the year following completion of cardiac rehabilitation. Extensive graphing and nonparametric tests were used on a longitudinal dataset collected from a cohort of cardiac rehabilitation patients to analyze how patterns of depressive symptomatology trended in relation to patterns of physical activity, diet, and alcohol use over time. An exploratory focus of this study assessed possible sex-based differences in these patterns. Results showed that depressive symptomatology decreased in the year following cardiac rehabilitation independently of diet or alcohol use. Patients who reported higher depressive symptomatology consistently reported lower frequencies of physical activity. Women reported higher depressive symptomatology than men over time. Further studies are warranted to elucidate how male and female cardiac patients differ in their manifestations of depressive symptomatology and the relationships between depression and health behaviors promoted in cardiac rehabilitation.