The effectiveness of doctoral programs has been a major topic of interest for national policies, universities, and researchers for decades now. However, studies that try to identify factors associated with doctoral students’ success usually focus on characteristics measured during doctoral training, while the role of pre-doctorate characteristics remains underexplored. This research aims to fill this gap by examining whether and how various aspects of pre-doctorate experience–academic achievements, research experience related and unrelated to the dissertation topic, and teaching experience–contribute to the successful defense of the doctoral dissertation. Using data from a survey of the Russian doctoral programs’ graduates (N = 985) and regression analysis, we show that research experience related to the dissertation topic is the only pre-doctorate characteristic associated with the successful defense of the dissertation. At the same time, the effect of this type of research experience vanishes when controlling for support from the supervisor and department that students receive during their training. The results of the study can be used for designing criteria for doctoral students’ admission campaigns and introduction of integrated, or fast-track, doctoral programs, as well as to broaden our understanding of the relative importance of environmental vs. individual factors of doctoral students’ outcomes.