The willingness to actively contribute to more sustainability bares important challenges for managers who must take strategic decisions. The literature about corporate social responsibility has developed in many directions, with often a divide in focus, between society (Acquier & Aggeri, 2015) or corporate sustainability and responsibility (Bansal & Song, 2017). The paper sits at the intersection of these fields by focusing on the question of ethical dilemmas. The objective is to approach the question of ethics in context, through the trade-offs that managers are facing when taking strategic decisions to build sustainable business models, to discuss the contours of the ethical competences at work. The paper focuses on a specific context, the one of successful pure players of sustainability in the luxury fashion industry. It means first that we leave aside the question of organizational change to analyze the core dilemmas that even new actors that start from scratch must face. These pure players could also be named “social entrepreneurs” (Elkington & Hartigan, 2008) or “elegant disrupters” (Bendell & Thomas, 2013). Second, by focusing on luxury fashion we locate our analysis in an industry where the nature of the activity is both a source of salient controversies and of exemplary practices (Kapferer, 2010; Godart & Seong, 2014), two aspects that have the potential to make visible some dilemmas. We focus on a small number of cases of organizations that we selected per criteria of similarities and differences, to allow for an inductive in-depth comparative case study (Yin, 2009). The four organizations are: a producer of yak products, a fur recycling company, a fur auction house and a digital platform for emerging designers. The cases are similar in that each organization is a successful promoter of sustainable practices. The four cases however differ in that each puts at the core of the business model different types of sustainability issues and is based at a different level of the value chain (sourcing, fabrication, intermediation and market access). Also, the four organizations differ in the degree to which they aim to disrupt existing practices in the luxury fashion industry. Data were collected through a series of interviews and complementary press articles, websites and reports. Data analysis proceeds in two steps. We start by narrating each case through the voice of the organization, to describe and understand the rationale behind each business model. We then further our interpretation of the cases through a comparative analysis by systematically recording the tensions or contradictions. Each firm organizes the activity around key engaging choices that promote sustainability but do not lift some inbuilt dilemmas–labelled as: sustainability vs. luxury fashion, sustainability vs. sustainability, and sustainability today vs. tomorrow. The paper highlights how innovative players can openly discuss some dilemmas, approaching sustainability as a story they care about but also as a debate. Yet, the paper also points to the fact that some dilemmas may remain harder to reflect upon, especially the ones that can counter in the long-run the objectives that were at the base of the business. Some questions as the one of growth, in time and scale, might push far the reflexive ability but it is also where ethical competences might be the most needed.