Medical social workers (MSWs) engage in complex and demanding work that inevitably affects their professional well-being. A public health disaster like coronavirus disease 2019 (COVID-19) exacerbates the effects. This study aims to classify the professional quality of life (ProQOL) of MSWs during COVID-19 in mainland China. It further examines the relationship between ProQOL classification, post-traumatic growth (PTG), and demographic characteristics. ProQOL comprises three domains: compassionate satisfaction, burnout and secondary traumatic stress. About 345 MSWs completed questionnaires that measured their levels of ProQOL and PTG. Through a k-mean cluster analysis, three clusters of ProQOL are identified. The first type is named as the Career Satisfied group, characterised by MSWs with the highest level of compassionate satisfaction and the lowest level of secondary traumatic stress and burnout amongst the three clusters. The second cluster is called the Trauma-Thriving group, consisting of MSWs with the highest level of secondary traumatic stress amongst all. They also had the highest score for PTG. The third cluster, the Compassion Fatigue group, comprised MSWs with the highest burnout and lowest compassion satisfaction levels. The results underscore the importance of tailored interventions for each type of MSW that emerges in a public health disaster. This study examines the impact of coronavirus disease 2019 on medical social workers' (MSWs) professional quality of life (ProQOL) and post-traumatic growth (PTG). ProQOL comprises three domains: compassionate satisfaction, burnout and secondary traumatic stress. About 345 MSWs from mainland China completed a questionnaire that collected information about their ProQOL and PTG levels. Using a statistical analysis method, the study uncovered three ProQOL types. The first type, the Career Satisfied group, consisted of MSWs with the highest level of compassionate satisfaction and the lowest level of secondary traumatic stress and burnout amongst the three types. The second type, the Trauma-Thriving group, comprised of MSWs with the highest level of secondary traumatic stress. They also scored the highest for PTG. The third cluster, the Compassion Fatigue group, comprises MSWs with the highest burnout and lowest compassion satisfaction. MSWs require tailor-made support according to their type.