Job satisfaction is a subject with a long tradition of research behind it. Now that people have a longer working life, as a result of demographic change, job satisfaction is increasingly in the spotlight. Given the change in the population's age structure, this study aims to analyse the construct of job satisfaction and its development over a person's lifetime. Reviewing classical models of job satisfaction, and considering approaches to career development and corresponding theories from developmental psychology, it indicates connections between job satisfaction and age. This study ultimately combines empirical evidence on the development of job satisfaction across the individual life span with approaches derived from the philosophy of science, and it discusses explanatory approaches to a potential progressive line in job satisfaction.