The sustainable shift is changing the fashion system at all levels in terms of products and practices, from processing raw materials to garment production, from communication to how people care for and dispose of their clothes. This setting generates new responsibilities and opportunities for all actors in the supply chain, including designers, who can influence different aspects of the process by making conscious design decisions. It means for designers to adopt a Life Cycle Design (LCD) approach, a methodology that design research for sustainability has developed recently and is now being transferred to fashion and its branches. Among these, the chapter focuses on the knitwear sector. It explores the possible scenarios knit designers face when adopting an LCD approach regarding the environmental sustainability of production processes and finished products. In a world where knitwear production is increasingly fragmented and globalized, what elements must designers evaluate to ensure that production has the least possible impact on the environment? What are the effects of design decisions along such an articulated supply chain? How can designers relate with stakeholders when the traditional structure evolves under new sustainable requirements, introducing new players and assets, and thus new challenges and opportunities? Given the urgency for academic education to prepare future knitwear designers capable of integrating sustainability into their designs, the chapter describes possible paths to acquire a design process that can provide tools to preserve environmental prerogatives and values.