A key problem in improvisation pedagogy is to understand the learning involved. However, different research fields’ attempts to articulate improvisational knowledge show that this is a contested space. The current chapter aims at challenging the epistemological view that learning must be seen as individual, vertical movements from one explicit level to the next. An anecdote from a bachelor performance exam of a fourth-year drum student serves as an example for addressing different issues at stake. I discuss how the concepts of expansive learning and horizontal development can contribute to our understanding of the learning involved when developing as improviser. In theorising knowledge in improvisation practices, there is a need to acknowledge inherent contradictions between for example standardised learning goals and creative freedom, and the fact that learners may challenge learning contexts as a response to such contradictions. If we understand learning and development as potentially multidirectional, we will be able to recognise a broader range of creative learning processes.