The purpose of this paper is to explore newcomers as active participants within their own socialization, through the influence of self-leadership on proactivity and subsequently organizational socialization and organizational commitment. Data collected from 193 organizational newcomers (i.e. individuals within their first year at an organization) working in a variety of industries were examined within three serial mediation models in PROCESS. The results of these analyses suggest that self-leadership influences organizational newcomers’ adjustment and subsequent commitment by assisting them in seeking organizational resources. This study answers calls to explore both the mediating mechanisms through which self-leadership processes influence organizational outcomes and the complex relationships between human workplace interactions and the proximal and distal outcomes of socialization. The findings indicate that organizational stakeholders should enhance the self-leadership abilities of newcomer, thereby easing the socialization burden on organizations. This paper offers a novel framework (i.e. self-leadership) for understanding newcomer socialization and provides an encompassing model that recognizes individual capacities, communicative behaviors, adjustment and subsequent organizational attitudes.