Professions are undergoing a significant change in how they integrate environmental and social objectives into their core values. This article examines the situation in which those working in the project management profession are expected to work under contradictory sustainability constraints. In this article, we investigate the tensions project managers experience when addressing sustainable objectives. Results show that when tensions arise over sustainable objectives (temporality of objectives, organizational barriers, and lack of control), they are addressed only when anchored to an economic one in the form of a business case for sustainability. We also find that when matching traditional project objectives with sustainable ones is not possible, practitioners enact a set of reactions characterized as greenwashing, it can’t be one person, no space for sustainability in my job, other actors involved, or pushing back, depending on the specific project context. Adopting the paradox theory lens, we provide an alternative approach to the business case for sustainability. The practical contribution of this article lies in suggesting the need to find strategies to embrace paradoxical situations and we provide some suggestions to illustrate this.