["Corporate Social Responsibility and Environmental Management, EarlyView. ", "\nABSTRACT\nThe significance of fostering an internal corporate social responsibility (ICSR) plan to advance employee well‐being is not fully understood. This article explores employee well‐being from a positive balance perspective, combining the strategic approach to Internal Corporate Social Responsibility with the Theory of subjective well‐being. Drawing on Sirgy's hierarchical model of well‐being and the Job Demands‐Resources. Framework, the study positions well‐being as a multidimensional construct shaped by both organizational practices and individual experiences across various life domains. The main goal is to identify and model the factors that determine employee well‐being within the organizational environment. The empirical analysis uses data from the European Working Conditions Telephone Survey 2021 (EWCTS 2021) (Eurofound 2022), covering a representative sample of 11,221 employed individuals across EU countries and the UK. Sets of variables structured in three blocks (traditional factors, organizational factors, and personal conditions) were tested. For estimation, the weighted logistic regression, multinomial regression, and Tobit models are used. For capturing cognitive, emotional, and eudaimonic aspects of well‐being, subjective well‐being is analyzed as a binary outcome (high vs. low well‐being), as a trichotomous variable (low, medium, and high levels), and as a continuous index. The results show that employee well‐being is associated with ICSR practices through a structural mechanism, which connects with the job demands–resources framework and the Positive Balance perspective, integrating different dimensions and levels of well‐being. The modeling strategy identifies a nonlinear pattern in which the intermediate level of well‐being emerges as a transitional zone between low and high well‐being. At this level, ICSR‐related factors exhibit weaker associations, and the overall configuration of well‐being determinants becomes less uniform. More institutional ICSR practices, including organizational participation, are less popular, which may indicate that positive balance mechanisms are not completely engaged. The consistency of the results across alternative model specifications reinforces the view of internal corporate social responsibility not only as an ethical commitment but as a strategic enabler of organizational sustainability and resilience, through a differentiated, employee well‐being–centered approach. These findings suggest that ICSR policies should be designed in a differentiated manner, combining managerial strategies aimed at activating employee well‐being across different states with broader social objectives related to sustainable work, quality of working life, and social well‐being.\n"]