In recent decades, psychopathology research has established significant evidence in support of a dimensional diagnostic model, in which maladaptive personality traits underlie and predict clusters of mental health symptoms. In this framework, psychopathology may be defined as maladaptively high or low levels of a personality trait causing distress and/or impairment. This literature, however, has yet to characterize the specific relationship between these traits and impairments in functioning (e.g., physical functioning, social functioning, mental health functioning). The current study aims to address this gap in the literature by (a) augmenting the measurement of personality traits along their full range by integrating cognate traits from the “maladaptive” and “normative” personality literature onto unidimensional personality spectra; (b) modeling the nonparametric relationship between newfound personality traits with functioning; (c) explore how these relationships are moderated by age and sex; and (d) validating initial findings using replication and confirmatory procedures in a second sample. Data for this study were collected, using item-sampling techniques, from an online personality questionnaire where individuals self-selected to participate in exchange for feedback on their personality profiles. The overall sample included 214,420 people (split into two samples of 107,210 individuals each) from 223 countries. Results provide support for the replicability of the relationships between personality and functioning. Evidence suggests these relationships are not linear and monotonic, but rather optimal functioning occurs between the extreme ends of the trait. Age and/or sex play different roles in moderating these relationships depending on the personality trait of interest. Future research is needed to address measurement problems which interfere with measuring the full spectrum of each personality trait.