The architecture, engineering, and construction (AEC) industry plays a pivotal role in driving global decarbonization efforts through the adoption of low-carbon building practices. However, the transition toward sustainable construction is influenced by a complex interplay of technical, economic, social, and process factors that extend beyond technological advancements. This research investigates the motivations, barriers, and decision-making processes within the techno-socioeconomic domain to enhance sustainability in a case study project. While multiple guidelines and standards for sustainable building design exist, none require a comprehensive techno-socioeconomic analysis. This paper presents a review of existing assessment methods, decision-making models, and decision support systems to identify the main dimensions, key performance indicators, and measurement methods for sustainable design. Subsequently, interviews with key stakeholders in a case study project capture their perspectives on factors affecting sustainable decision-making. This multifaceted approach enables the identification of dimensions that exist in real-world projects as drivers and barriers to sustainability, comparing them with the theoretical guidelines. The long-term goal of this research is to develop a framework that bridges the gap between theory and practice, providing a holistic approach to sustainable building design decision-making. This framework encompasses a comprehensive set of sustainable building design dimensions and their corresponding key performance indicators. Practical methods for assessing and quantifying the dimensions based on the insights from real-world case studies will be proposed to guide decision-making.