Purpose The purpose of this paper is to explore the ways engineering doctoral students draw on prior experiences to inform their doctoral research. This study includes the experiences of “returners” – those who have worked as practitioners for five or more years before entering a PhD program – who have distinct experiences from “direct-pathway students,” which may inform how they engage in doctoral research. This study also explores the traits that distinguish varying levels of sophistication in the ways PhD students think about the research process and how prior experience may contribute. Design/methodology/approach This study draws on interview data from 52 returning and direct-pathway engineering doctoral students. A thematic analysis of this interview data highlights the primary ways participants’ prior professional, academic and life experiences inform their doctoral research. In addition, the authors conducted an iterative analysis process to sort participants’ responses about their management of a hypothetical research scenario into emergent categories of research thinking sophistication to understand what characterizes varying levels of sophistication in research thinking and explore how experience may contribute. Findings Participants identified past experiences as shaping their research, related to how they identify a research problem, considering what needs to and can be done to address the problem, identifying an appropriate research approach, managing unexpected challenges, responding to critical feedback, determining their comfort taking risks and using intuition to lead a project. Originality/value Outcomes of this research can inform how graduate education supports students throughout their degree by identifying key experiences that may contribute to students’ research approaches.