Nepotism, altruism, lower managerial abilities, and a small pool of qualified family candidates may speak against family management. However, a large share of family-owned firms is run by family managers. Our study develops a theoretical model that provides an explanation for this paradox, linked to the multitasking problem of managing economic and non-economic tasks in family firms. Comparing the performance of family and non-family managers under moral hazard and imperfect performance measurement, we find that incentive pay leads to an effort distortion towards economic outcomes for both manager types, however less so for family managers. This effort distortion is less pronounced when economic and non-economic management tasks are complements. We show that family managers with excellent skills regarding non-economic goals of the owner family often outperform non-family managers even if they have poor skills in economic tasks or, what is more, if they have lower average abilities altogether. We further show that the interdependence between economic and non-economic goals in the manager's job tends to have a moderating effect on the family manager's relative performance. Our study contributes to the literature about family management and agency costs in family firms and has practical implications for family firms' hiring decisions. By highlighting the importance of non-economic goals, it moreover adds to the current discussion about the compliance with firms' sustainability goals. Plain English Summary: Family firms are the most common firm type around the world. Many of them, also those in later family generations, are run by members of the business-owning family. This is surprising since prior research has identified strong reasons that speak against family management such as nepotism, altruism, lower managerial skills, and a small pool of qualified family candidates. Our study contributes to solving this puzzle by developing a theoretical economic model. We show in this model that hiring a family manager is oftentimes the optimal decision when managers have to perform multiple tasks and, more specifically, need to take care of both economic and non-economic goals of the business-owning family. Non-economic goals comprise family goals (e.g., maintaining family harmony, reputation, tradition, and dynastic control) but also stakeholder-oriented sustainability goals (e.g., maintaining good relations with employees and avoiding environmental pollution). Achieving such non-economic goals, however, is often interrelated with economic tasks or goals. For example, to become a stable and highly reputable employer implies that you may have to forgo shutting down an unprofitable business unit, which saves jobs but has negative consequences for the firm's competitive position and financial performance. This interrelationship between the two tasks or goals, together with the fact that the achievement of non-economic goals is often more difficult to measure than the achievement of economic goals, makes it difficult to provide effective managerial incentives for them. We find that, under incentive contracts, non-family managers direct more attention towards economic goals while family managers, as such, are more reluctant to neglect non-economic goals. That is why family managers may be the optimal hiring choice despite them often having lower abilities across the two tasks. With the results from our theoretical model, our study contributes to the literature on family managers and agency costs in family firms by providing a new explanation for the high prevalence of family managers in family firms, namely the agency costs resulting from the managers' multitask problem in family firms. By highlighting the importance of non-economic goals, our study moreover adds to the current discussion about how to select and incentivize managers to pursue (social and environmental) sustainability goals. Our study has practical implications for family firms and their hiring practices regarding family members. In fact, we show that, in many cases, it is perfectly reasonable and meaningful to select and hire a family manager to run the family business even if he or she exhibits relatively weak skills in economic tasks. The relative benefit of family over non-family managers increases with a higher importance attached to non-economic (sustainability) goals by the owner family, with a better measurement of a manager's achievement regarding these goals, and with a stronger reinforcing interdependence between economic and non-economic goals. [ABSTRACT FROM AUTHOR]