This article aims to extend the traditional Ecological Interface Design (EID) process.With the rapid pace of digitalization in technological systems, there is a need for a design process that can handle the systemic design goals and the experiential basis of interaction. Currently, the traditional EID is well-positioned to address these challenges. However, methodologically, it needs to be substantiated to make it accessible for designers, designing for novel arenas, such as Industry 4.0. Further, substantiating the design process will help designers, engineers, and human factors researchers with an accessible pathway that links the design brief to the final interface form. Therefore, this article delves into the "design" basis in the work of the Risø group and other prominent EID researchers and practitioners. In addition, it draws from a variety of themes in the discipline of design that addresses methodology. In particular, key insights are drawn from the design methods movement (1960s-); design, communication, and complexity from the Ulm school of design, 1953-1968; cognitive research conducted on designers and design activities; and finally, interaction design and communication design processes and models. All of these insights have been used syncretically to create the new integrated EID (iEID) process. This new design process consists of nine stages divided into three phases of divergence, transformation, and convergence, converting the initial design brief to the final interface. The steps of iEID are demonstrated using the example of interface design for a "digital twin" in the manufacturing sector.