Research on the career trajectories of doctoral recipients often assumes that all PhD students begin in roughly the same starting position. Consequently, the impact of pre-programme experiences remains understudied. This qualitative study draws on 59 interviews with PhD students studying in mainland China and Hong Kong to explore the influence of learning experiences during the master's degree programme on planned PhD career trajectories. Using identity-trajectory theory, we find that students with a master's degree had greater research expertise, a more prominent research profile, more established academic networks, and greater familiarity with the requirements of the academic profession and academic job market. This enabled them to adapt to institutional expectations and have a better-informed motivation for pursuing a PhD to become an academic. Based on these findings, we argue that having a master's degree gives PhD students a competitive advantage over peers without master's degrees. Our findings have implications for the importance of research training in master's education and the relevance of master's programmes for PhD admission policies.