Despite decades of acknowledging improvisation's importance for organizational adaptability, its full potential remains unrecognized. Consequently, many organizations, particularly in healthcare, hesitate to actively promote improvisation. This hesitation comes from a gap in research, which has considered individual and group improvisation separately but not how they connect or how they benefit organizations’ work. To address this gap, we conducted a qualitative study involving interviews with nurses, doctors, and administrative staff in clinical departments in two US-based healthcare systems during the COVID-19 pandemic. We identified four improvisation patterns: individual, collective, continuum (starting as individual and transitioning to collective), and mutually enabling (shifting between individual and collective improvisation). These patterns are predicted by a variety of task characteristics, individual traits, and contextual factors, and lead to diverse outcomes in healthcare settings. Through a comparison of predictors, processes, and outcomes between individual and collective improvisation patterns, our study enriches improvisation theory and informs effective improvisation within organizations.