Over the past couple of decades organizations have become increasingly flat and decentralized, and have began to emphasize a more active role for employees in their own job management and development. As a result, the concept of employee proactivity has been a growing area of theory and research. Within the workplace, proactive people are conceptualized as those who take initiative to improve their current circumstances, and take active rather than passive roles within their current positions. These employee characteristics have been shown to be desirable in various situations, resulting in beneficial employee and organizational outcomes, such as promotions, career success, innovation, self-efficacy, and perceived insider status. Of particular interest for the current study, employee proactivity has also been linked to successful socialization outcomes. The socialization period can be very important for employees in determining their future relationship with their employers and their future success in the organization. Research has examined the role that a proactive disposition and proactive behavior can play in the socialization period. Additionally, researchers have looked into the relationship between proactive personality and various employee characteristics, including proactive behavior. However, there has been little research on the link between proactive dispositions and various behaviors and characteristics from job entry and throughout the socialization period. The current research aims to fill this gap in the literature by examining proactive personality and various behaviors and characteristics during the socialization period. Specifically, it was hypothesized that proactive personality will predict feedback seeking, self-efficacy, goal clarity and fit. Additionally, it was hypothesized that changes in self-efficacy, goal clarity and fit would be related to changes in feedback seeking throughout the socialization period. Participants were 188 management trainees from an international transportation company based in the eastern United States. A repeated measures design was used, and the participants received online surveys at five time points throughout their training. Multilevel slopes-as-outcomes analyses were used to test the first set of hypotheses on the relationship between proactive personality and other variables, and parallel process growth modeling was used to assess the second set of hypotheses on the relationship between changes in variables over different time points. Results showed that proactive personality significantly predicted changes in feedback seeking throughout the socialization period, such that individuals with proactive personalities were more likely to increase their feedback seeking behaviors throughout the socialization period. Additionally, it was shown that there was a significant positive relationship between the changes in feedback seeking behaviors and changes in reported levels of goal clarity. The results of this study can provide organizations that desire a more proactive workforce insight into how employee proactivity is related to other desirable characteristics, and how the display of proactive behavior can change throughout the socialization period.