Comprehensive knowledge of factors causing and sustaining functional impairment in patients with affective disorders is warranted. The aim is to investigate associations between clinical factors (such as affective symptoms) and personal factors (such as personality traits, coping strategies, and childhood trauma experiences) on functioning and improvement of functioning in patients with affective disorders. This exploratory study includes data from 103 patients with bipolar disorder and unipolar depressive disorder. Clinician-rated functioning was assessed at baseline using the Functioning Assessment Short Test (FAST), and performance-based functioning was assessed at baseline and 6-month follow-up using the Assessment of Motor and Process Skills (AMPS). Data on clinical and personal factors were collected at baseline. Personal factors were measured by the Eysenck Personality Inventory (EPQ), Coping Inventory for Stressful Situations (CISS) and Childhood Trauma Questionnaire (CTQ). Pearson correlations and multiple linear regression models were used to analyse the association of clinical and personal factors with baseline functioning (FAST) and to identify predictors of improvement in functioning (AMPS) from baseline to follow-up. At baseline, greater depressive symptom severity, the personality trait neuroticism, emotional coping, and childhood trauma all correlated with poorer functioning (higher FAST scores). In multiple linear regression models, depression severity, emotional coping and childhood trauma were significant predictors of poorer functioning. More childhood trauma was a predictor of less functional improvement measured by AMPS at 6-month follow-up. In conclusion, maladaptive coping styles and depressive symptoms contribute to functional impairment in patients with affective disorders, while childhood trauma has a negative impact on long-term functional outcomes.