Studies on the role of national parliaments in the EU have conventionally looked at the formal capabilities and activities of legislatures as collective actors. We aim to strengthen the bridge to the growing literature on the politicisation of the EU by examining individual-level mobilisation within the parliament. In order to enrich our understanding of the actors and inner workings that drive or impede the parliamentarisation of EU politics, we shift the focus from preferences to opportunity and incentive structures and levels of party control faced by different categories of MPs. Our case study of plenary debates on the Greek crisis in the German Bundestag (2010–2015) analyses three types of activity: legislative speech, voting defection and explanations of vote. Our results show that different thresholds of mobilisation translate into intra-party variance based on MPs’ rank, experience, electoral mandate and gender. Here, the frontbencher–backbencher categorisation shows the most consistent effect.