Research has identified improvisation as a creative and open activity that can be harnessed to encourage innovation and learning within the organization. In this paper, we present improvisation as a covert phenomenon, occurring in a climate of mistrust and fear of censure, and disconnected with wider organizational learning. Drawing on qualitative evidence of a Fire Service in the United Kingdom, we explore hidden improvisation, and identify the conditions and processes that can connect these local deviations to wider processes of learning. We show that while most improvisations remain hidden and contained to avoid wider scrutiny, certain conditions of frequency, connectedness and scale escalate events to become more visible to supervisors and managers. The learning outcomes from these visible improvisations will then depend on management’s interpretation, evaluation and translation of improvising behaviours. Dependent on prior relationships of trust and credibility, middle management perform a key brokering role in this process, connecting previously hidden improvisation to wider organizational systems and structures.