Paradoxically, school leaders as a group report high levels of burnout but also high job satisfaction and passion for their work. School principals are passionate about their job, but this passion can be a double-edged sword leading to good (job satisfaction) and bad (burnout) outcomes. We extend the dualistic model of passion (DMP) in a study of changes over a 1-year period (3,996 school leaders) in three components of work passion (general, harmonious, and obsessive), burnout, and job satisfaction. We begin by placing the DMP into a broader framework of passion research and how passion is related to other well-being constructs. We then develop the rationale for integrating within the same study the obsessive passion and harmonious passion constructs used in DMP studies and general passion used in most other passion studies, but also the inappropriateness of the exclusion strategy based on general passion in DMP research. We found that Time1 harmonious passion was related to job satisfaction (positively) and burnout (negatively), while the pattern of relations was the opposite of obsessive passion. However, over time, harmonious passion and obsessive passion were moderated by general passion. The protective effect of harmonious passion on burnout was smaller when general passion was high, while undesirable obsessive passion effects were only evident when general passion was high. School principals' work passion may help them avoid burnout and maintain high job satisfaction, but only when manifested harmoniously. We describe how future studies of longitudinal passion can be integrated into the broader job demands-resources model.