--- - |2 Summary The longstanding assumption in person–environment (PE) fit research is that perceived fit embodies the subjectively experienced match between personal and environmental attributes and hence triggers affect and behavior (i.e., normal causation perspective). This argument is however increasingly debated, with some scholars suggesting that the causal flow may also run from affect and behavior to perceived fit (i.e., reverse causation perspective), and others even arguing that perceptions of PE fit are not substantially different from how people feel and think about their environment (i.e., synchronous relationship perspective). In this research, we propose that these three competing perspectives correspond with different assumptions on how PE fit perceptions dynamically change over time (i.e., by means of comparative reasoning, logical deduction, or heuristic thinking). We empirically validate these three competing perspectives by teasing out the causal ordering of the within‐person relationships between perceptions of fit and workplace affect and performance. In two separate diary studies, one with weekly (N = 153) and one with daily (N = 77) repeated measures, support was found for the synchronous relationship perspective with heuristic thinking as the plausible underlying process. This research contributes to the PE fit literature by providing new insight into the dynamic nature of perceived fit. - Journal of Organizational Behavior, EarlyView.