<p>Against the backdrop of declining global rankings of subjective well-being among Chinese residents, the mechanisms through which educational attainment shapes well-being have emerged as a critical area of inquiry. Drawing on data from the 2021 Chinese General Social Survey (CGSS), the present study examines the pathways linking educational attainment to subjective well-being, with particular attention to the mediating role of language proficiency and the moderating influence of the Hukou system. The findings suggest that educational attainment is positively associated with subjective well-being, and that language proficiency partially accounts for this association. Moreover, the Hukou system moderates the association between educational attainment and residents’ language proficiency and moderates the indirect association between educational attainment and subjective well-being via language proficiency. These results provide novel insights into the complex interplay between education and well-being, offering important implications for the formulation of educational policies and the promotion of social equity.</p>