The fulfilment of psychological contracts has gained significant attention due to their impact on employee attitudes, behaviors, and well-being. With its distinctive organizational characteristics and transformations, the public sector presents a unique context to explore the association between psychological contract fulfilment and individual well-being outcomes (work engagement, overall job satisfaction, and overall life satisfaction). The theoretical foundation supporting these relationships was based on the Social Exchange Theory (SET), Job Demands- Resources Theory (JD-R), and the Spillover Effect. The moderating effect of the work format (telework, on-site, and hybrid) was also studied. A quantitative method with a cross-sectional and descriptive- correlational design was followed, using non-probability sampling techniques (convenience and snowball sampling) for data collection through an online platform (LimeSurvey) using a self-report research protocol. The total sample comprised 351 Portuguese public sector employees (72.6% women and 27.4% men). The results supported the positive relationship between psychological contract fulfillment and both work engagement and overall job satisfaction, as well as between overall job satisfaction and overall life satisfaction. However, no significant relationship was found between work engagement and overall life satisfaction. Additionally, the moderating effect of work format was not supported in any of the tested relationships. These findings highlight the crucial role of psychological contract fulfillment in increasing employee well-being in the Portuguese public sector. They also provide practical contributions to promote a healthy work environment, focusing on employee well-being across the various work formats.