Background: Depression is often characterized as a disorder of affect regulation. However, research focused on delineating the key dimensions of affective experience (other than valence) that are abnormal in depressive disorder has been scarce, especially in child and adolescent samples. As definitions of affect regulation center around processes involved in initiating, maintaining, and modulating the "occurrence," "intensity," and "duration" of affective experiences, it is important to examine the extent to which affective experiences of depressed youth differ on these dimensions from those of healthy youth. Methods: The affective behavior and experience of adolescents with major depressive disorder (MDD; n = 75) were compared to a demographically matched cohort of healthy adolescents (n = 77). Both samples were recruited from community high schools. A multi-source (parents and adolescent), multi-method (interviews, behavioral observations, questionnaires) assessment strategy was used to examine positive and negative affects. Results: Depressed youth had significantly longer durations, higher frequency, and greater intensity when experiencing angry and dysphoric affects and shorter durations and less frequency of happy affect when compared to healthy youth. The most consistent, cross-method results were evident for duration of affect. Conclusions: Clinically depressed adolescents experienced disturbances in affective functioning that were evident in the occurrence, intensity, and duration of affect. Notably, the disturbances were apparent in both positive and negative affects.