This two-year study with 122 business owners examined the link between affective well-being and task-oriented as well as relationship-oriented personal initiative (PI). We tested two complementary models explaining the link between well-being and PI: (1) broaden-and-build theory and (2) self-regulation as limited resource approach. In line with current research on well-being, we differentiated between hedonic and eudaimonic well-being using life satisfaction and vigor as indicators. Hierarchical regression analyses showed that only vigor predicted both forms of PI. Our results support the self-regulation approach and indicate that eudaimonic well-being is the relevant affective well-being dimension for proactive behavior.