Objectives COVID-19 has prompted the reconfiguration of hospital services and medical workforces in countries across the world, bringing significant transformations to the work environments of hospital doctors. Before the pandemic, the working conditions of hospital doctors in Ireland were characterised by understaffing, overload, long hours and work–life conflict. As working conditions can affect staff well- being, workforce retention and patient outcomes, the objective of this study was to analyse how the pandemic and health system response impacted junior hospital doctors’ working conditions during the first wave of COVID-19 in Ireland. Methods and analysis Using a qualitative study design, the article draws on semi- structured interviews with 30 junior hospital doctors. Informed by an abductive approach that draws iteratively on existing literature and empirical data to explain unexpected observations, data were analysed using inductive and deductive coding techniques to identify the key themes reflecting the experiences of working in Irish hospitals during the first wave of COVID-19. We use the Consolidated Criteria for Reporting Qualitative Research to present this research. Results Our analysis generated three themes which demonstrate how COVID-19 prompted changes in medical staffing which in turn enhanced interviewees’ work environments. First, interviewees felt there were more doctors staffing the hospital wards during the first wave of the pandemic. Second, this had positive implications for a range of factors important to their experience of work, including the ability to take sick leave, workplace relationships, collective workplace morale, access to senior clinical support and the speed of clinical decision- making. Third, interviewees noted how it took a pandemic for these improvements to occur and cautioned against a return to pre- pandemic medical staffing levels, which had negatively impacted their working conditions and well- being. Conclusions Interviewees’ experience of the first wave of COVID-19 illustrates how enhanced levels of medical staffing can improve junior hospital doctors’ working conditions. Given the pervasive impact of staffing on the quality of interviewees’ work experience, perhaps it is time to consider medical staffing standards as a vital job resource for hospital doctors and a key policy lever to enhance medical workforce retention. In a global context of sustained COVID-19 demands, pressures from delayed care and international health worker shortages, understanding frontline experiences and identifying strategies to improve them are vital to the development of more sustainable work practices and to improve doctor retention.