Purpose The coronavirus 2019 pandemic has placed all intensive care unit (ICU) staff at increased risk of psychological distress. To date, measurement of this distress has largely been by means of validated assessment tools. We believe that qualitative data may provide a richer view of staff experiences during this pandemic. Methods We conducted a cross-sectional, observational study using online and written questionnaires to all ICU staff which consisted of validated tools to measure psychological distress (quantitative findings) and open-ended questions with free-text boxes (qualitative findings). Here, we report our qualitative findings. We asked four questions to explore causes of stress, need for supports and barriers to accessing supports. A conventional content analysis was undertaken. Results In total, 269 of the 408 respondents (65.9%) gave at least one response to a free-text question. Seven overarching themes were found, which contribute to our proposed model for occupational stress amongst critical care staff. The work environment played an important role in influencing the perceived psychological impact on healthcare workers. Extra-organisational factors, which we termed the "home-work interface" and uncertainty about the future, manifested as anticipatory anxiety, had a proportionally larger influence on worker well-being than would be expected in non-pandemic conditions. Conclusion Our findings have important implications for appropriate allocation of resources and ensuring well-being of the ICU multidisciplinary team for this and future pandemics.