While important insights have been provided into the role of HR managers in performing change in the workplace, still little is known about how HR managers themselves are shaped by change, in particular in relation to those changes triggered by radical or disruptive shock events and crisis situations, and in the public sector context. In this study, we aim to address this, using an exploratory qualitative interview study to explore how the serious and profound COVID-19 pandemic triggered boundary work among HR managers in public sector municipalities. Our findings illustrate that COVID-19 triggered HR managers to engage in boundary work in two main ways: either by defending their boundaries (through the two practices of counteracting dumping and counteracting shirking) or by expanding them (through the two practices of facilitating self-fulfillment and facilitating status-enhancement). We discuss how this variation is related to whether the HR managers experienced and made sense of the pandemic mainly as a threat—of being forced into unwanted responsibility—or if they experienced and made sense of it mainly as an opportunity to take advantage of the situation. In showing this, the study makes a number of important contributions to both theory and practice. © The Author(s) 2023.