Professional Socialization is one of the types of socialization that refers to the process of learning roles, values, norms and skills related to profession or social groups. The purpose of this study is to explore the process of professional socialization among theater actors/actresses of Tehran as a professional group and exploration of processes, through which the beginner can be changed into a professional member of theater actors’ group.Achieving this goal is followed through understanding “The story of becoming an actor” of interviewees under conducting Grounded Theory. From context/conditions categories, “context of stimulus” was selected as abstraction core category and from process/ interaction categories, “maximum self-education” was selected as core category. Through combining the two categories, final central category was obtained: “maximum self-education in the context of stimulus”. The context of stimulus is sometimes agreed family background, sometimes disappointing environment of the university that acts as a motivating factor to develop action and sometimes morphological context provided by the university. Continuous and maximized self-education is also the main point in data, which has had the highest significance and impact in this process in view of respondents. This is an internal active motor that constantly seeks learning and gaining acting skills through different pedagogical sources.