An increasing body of social work literature has focused on professional virtues. However, this scholarship has often overlooked clients’ perspectives and failed to examine the relationship between professional virtues and their contribution to trust-building. Based on in-depth interviews with sixteen clients involved in a livelihood mutual aid project in China, this study analysed clients’ perceptions of social workers’ virtues and how these virtues contribute to trust-building. Thematic analysis revealed three major themes. First, clients initially regarded social workers as strangers, displaying mistrust and defensive behaviours. Second, clients came to view social workers as good people, which fostered trust, greater self-disclosure, and participation in group activities. Third, the virtue of prioritizing others over oneself, embodied by social workers, was central to clients’ recognition of them as good people. The study suggests that social workers seeking to build trust with clients should first aim to demonstrate virtuousness through prioritizing others over themselves. Future research could further explore how to promote virtue-led social work practice.