The research’s main objective is to examine the mediating role of Employee Commitment (EC) in the relationship between Flexible Work Arrangements (FWAs) and employee behavior (Innovative Work Behavior (IWB) and Employee Performance (EP)) among employees in the Republic of Serbia. The research consists of a theoretical part (review of the literature on previous theoretical and empirical findings) and an empirical part (Partial least squares structural equation modeling (PLS-SEM) analysis conducted on a sample of 582 employees in Serbia). The main findings have determined that there is full mediation, as the indirect effect of FWAs on Innovative Work Behavior through employee commitment is significant, and partial mediation, as the indirect effect of FWAs on Employee Performance through Employee commitment. The flexibility provided by FWAs not only increases employee satisfaction and loyalty but also motivates them to reciprocate through improved behavior and employee performance. In this way, employee commitment becomes a key factor that links organizational flexibility policies with positive outcomes in employee behavior. Flexible work arrangements are key to HR sustainability by enabling a better work-life balance, reducing stress, increasing employee commitment, and fostering long-term innovation and productivity. The mediating role of employee commitment in the relationship between flexible work arrangements and employee behaviors, such as innovative work behavior and employee performance, is particularly important. A high level of commitment, which stems from flexible work conditions, significantly contributes to innovative practices and improved performance, further strengthening the sustainability of organizations.