Although research on parasocial interactions (PSI) has over 50 years of tradition, it provides a heterogeneous status of measurements and findings. The challenge for present and future PSI research is to provide measurement standards that are generated, confirmed, and validated across several studies. The present contribution tries to take a first step in this direction by exploring PSI with (1) nonmediated fictional characters (theater), (2) mediated fictional characters (soaps), and (3) mediated nonfictional characters (quiz shows). All three studies are based on the same theory (Two-Level Model of PSI) and on parts of the same corresponding measurement tool (PSI-Process Scales). All in all, the PSI-Process Scales show high usability in all three contexts, with the option to select PSI dimensions and items with respect to the study's focus. Even in a theater play, the PSI-Process Scales could be applied without any problems and without any changes in the item wordings. The results of the three studies offer new insights into the importance of specific user and persona characteristics for the constitution and intensity of PSI in different media genres.