Social work is a typical form of emotional labour, and Chinese social workers face political-market dual embeddedness with limited resources and systemic challenges. Yet prior research ignores how career choice motivations shape their emotional experiences and links individual factors to organizational mechanisms. Using a sample of 5,303 participants from the China Social Work Longitudinal Survey 2019, the study applied ordinary least squares (OLS) and Karlson-Holm-Breen (KHB) methods to explore the relationship between career choice motivations and social workers’ emotional experience via emotional labour theory. Findings indicated that internal motivation significantly reduced burnout and enhanced perceptions of job performance. External motivation showed a significant positive relationship with job burnout and a negative relationship with perceived job performance. Organizational identity mediated the relationship between career choice motivations and emotional experiences. Placing the research focus on the relationship between motivational factors and emotional outcomes, this study reveals the positive and negative effects of emotional labour on social workers. It responds to the commodification of social work under neoliberalism, which may have further contributed to the negative outcomes of emotional labour. The findings underscore that prioritizing ethical education, fostering internal motivation in social workers, and creating a supportive organizational climate can ameliorate burnout amongst social workers.