According to the Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition (DSM-5) alterative model of personality disorders, severity of personality dysfunction theoretically involves deficits in identity, self-direction, empathy, and intimacy. We predicted that people with greater personality dysfunction would experience more problems in daily life, particularly problems associated with self-efficacy for engaging with affect and self-control (i.e., subjective willpower and distress intolerance), along with greater intensity of life stressors and higher perceived invalidation from others. Using ecological momentary assessment, participants (N = 99) were randomly prompted 7 times a day for 1 week, where they were asked questions about momentary affect, their perceived level of momentary distress tolerance, and their momentary willpower. Each night they were also asked about stressors experienced that day and intensity of their subjective response to those stressors and their daily experience of being invalidated. Results found that higher personality dysfunction, assessed at baseline, predicted greater daily negative affect, less daily positive affect, more intensely experienced stressors, and more perceived invalidation. We also found that personality dysfunction interacted with positive affect in predicting momentary self-efficacy and daily invalidation; people with greater personality dysfunction experienced lower momentary willpower, higher distress intolerance and stronger perceived invalidation alongside lower positive affect. These findings provide evidence that personality functioning influences daily life as well as support the use of the alterative model of personality disorders in conceptualizing personality pathology. (PsycInfo Database Record (c) 2021 APA, all rights reserved).