This study examined the impact of approach job crafting on social workers’ job performance, with work meaningfulness and work identity serving as mediating variables. Data were collected through questionnaires distributed to social workers in Taiwan, resulting in 802 valid responses from 856 distributed instruments (93.7 percent response rate). Data analysis was conducted using SPSS 21.0 for descriptive statistics and AMOS 21.0 for structural equation modeling to test the hypothesized relationships. Results demonstrate that the principles of self-determination theory and work identity theory, when applied through approach job crafting, significantly enhance social workers’ job performance, work meaningfulness, and work identity. The study confirms that approach job crafting influences job performance through dual pathways: directly and indirectly via the mediating effects of work meaningfulness and work identity. As the social work profession confronts increasingly complex challenges, understanding mechanisms to enhance practitioners’ effectiveness becomes critical. This research provides evidence-based recommendations for social work practice, offering pathways to promote career development and psychological well-being among social work professionals.