The Dualistic Model of Passion has gained increasing attention in social psychology in the past decade. Besides defining passion as “a strong inclination or desire toward an activity that one likes, finds important, and in which one invests time and energy” (Vallerand et al., 2003, p. 757), it acknowledges two types of passion, harmonious and obsessive, which develop according to how individuals internalize an activity in their self‐concept. A growing body of empirical research, particularly in nonwork settings, has demonstrated that harmonious passion and obsessive passion have distinct outcomes. As such, this two‐dimensional passion construct may be particularly useful for developing a more comprehensive understanding of how individuals engage with work compared to the existing one‐dimensional constructs of job engagement used in organizational literature. The present study develops hypotheses and tests the direct effect of harmonious and obsessive passion with work satisfaction. It also aims to develop theory by connecting the dualistic passion approach with work–life conflict; in doing so, it tests how individuals' off‐task thoughts at work and on‐task thoughts off work may mediate this relationship. Using a quantitative survey, the hypotheses are tested on a random sample of individuals engaged in business start‐ups in Sweden. Whereas harmonious passion exhibits a direct effect with work satisfaction, obsessive passion exhibits an indirect effect through on‐task thoughts off work with work satisfaction.