This study seeks to achieve a dynamic person-centered understanding of the nature of the psychological capital trajectories observed among upcoming police officers undergoing vocational training. Moreover, it seeks to document the predictive role of leader-member exchange and perceived organizational support in relation to these psychological capital trajectories, as well as the implications of these trajectories for a variety of outcomes related to trainees' attitudes (i.e., organizational cynicism, identification with the organization, engagement in the training program, and satisfaction toward the training program), psychological health (i.e., perceived stress), and behaviors (i.e., performance in the training program). A sample of 1200 participants undergoing a 33-week full-time vocational training program to become police officers were surveyed four times over a period of five months and a half. Results revealed that psychological capital trajectories corresponded to five primary profiles: Learning to Hate, High Fit, Moderate Fit, Honeymoon-Hangover, and Low Fit. Perceived leader-member exchange and organizational support were associated with these trajectories in a way that mainly supported our expectations. Trajectories characterized by lower levels of psychological capital were associated with higher levels of cynicism and stress, and with lower levels of engagement, identification, performance, and satisfaction. Conversely, trajectories characterized by higher levels of psychological capital were associated with the most positive outcomes. Defined as a psychological resource encompassing the experience of hope, resilience, optimism, and efficacy (Luthans & Youssef, 2004), psychological capital represents a key driver of well-being, performance, and positive functioning (e.g.,