Affective experiences at work are a key contributing factor to long-term job-related well-being and effectiveness, yet may systematically change as workers get older. Given the central role of affect in work settings, it is important to obtain a thorough understanding of older workers' strengths and vulnerabilities in affective functioning. This paper's goal was to comprehensively study age differences in mean levels and dynamics of affect (affect stability, occurrence of positive and negative daily work events, and affective reactivity) and to link these with perceptions of global occupational well-being and effectiveness. In three diary studies, employees of different occupational and cultural backgrounds (Hong Kong Chinese managerial employees, German hospital employees, German office workers) reported daily affective work events and affect across multiple workdays. Higher age was associated with more positive and less negative affect (Study 1), more frequent positive daily work events (Study 2 and 3), and lower variability of negative affect (Study 1 and 2). Age was unrelated to frequency of negative work events and positive event reactivity (all studies). There were mixed age differences in negative event reactivity (lower reactivity in Study 1 and on subtypes of affect in Study 2, but higher worry in Study 3). Several of the indicators of affective experience emerged as mediators of positive age differences in work engagement and self-rated task performance. Overall, with one exception, results point at maintenance or improvement of workers' affective functioning with age. Through improved affective functioning, older workers likely contribute to organizational effectiveness.