The goal of the present study was to explore how self-disclosure (SD) and immediacy relate to trainee therapists' personal characteristics. A prospective multitrait multimethod assessment approach was utilized to assess a wide range of trainee characteristics at the beginning of graduate school. Results showed a significant, positive relationship between trainee interpersonal problems and SD for trainees (n = 33) in their third psychotherapy session with their first patient. Moreover, greater use of SD correlated with less session depth, as rated by the trainee. Greater use of immediacy was positively related to trainee undergraduate grade point average and trainee-reported post-session arousal. Notably, all statistically significant findings had a moderate magnitude of effect. Finally, qualitative analyses of the SDs and immediacy statements were included to aid the discussion of potential reasons for the results. Overall, our findings provide preliminary conclusions about which trainees utilize SD and immediacy, what types of SDs and immediacy interventions they tend to use, and how trainees and patients perceived the session in which SD and immediacy were implemented. Implications for supervision and training are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).