Proactive newcomers are more successful in terms of integration and job satisfaction, than newcomers who are less proactive. However, it is unclear whether contextual factors, such as the leadership style experienced by newcomers, matter. To address this gap in the literature, we gathered data at three times from 247 new employees across their first six months after joining a company in France. Given that past research has found that newcomers play an active role in their own adjustment process, in the current study we investigate how newcomer proactive behaviors relate to the key outcomes of job satisfaction, person-job fit, and person-organization fit. We examined the degree to which servant leadership moderated the proposed relationships. Results revealed that servant leadership generally benefited employee socialization outcomes, especially for employees low in proactive behavior. But at low levels of perceived servant leadership, followers were able to compensate for this leadership deficiency the more they engaged in proactive behaviors. Although proactive behaviors did not surpass servant leadership in relationships with job satisfaction, P-J, and P-O fit, follower proactive behaviors had the strongest relationships to these outcomes under conditions of low servant leadership. Specifically, the results suggest that newcomer engagement in proactive behaviors is especially important to newcomer adjustment when leaders exhibit low levels of servant leadership. •Across their first six months on the job, new organizational members played an active role in their own adjustment.•Information seeking and general socialization relate to job satisfaction, person-job fit, and person-organization fit.•Servant leadership served as an important contextual boundary condition of these relationships.