The construction industry faces various sustainability challenges, and modern methods of construction (MMC) have been promoted as an effective alternative to mitigate environmental impact and improve productivity. However, to gain a thorough understanding of the benefits, there is a need for more objective data. To address this, the present study employs a simplified life-cycle assessment (LCA) methodology to evaluate a set of environmental and efficiency metrics in a case study. The study aims to demonstrate the benefits of using an MMC known as the “VAP system” by comparing it with its conventional counterpart built with reinforced masonry. Adopting the MMC resulted in significant reductions in embodied carbon (EC) and embodied energy (EE) related to materials, as well as a reduction in global warming potential (GWP), cumulative energy demand (CED), and construction waste. Additionally, it shortened delivery times and increased labor productivity. Furthermore, when both local and European parameters were considered in the evaluation, the percentage of materials circularity (PMC) was higher. The study concludes that the adoption of the MMC leads to higher sustainability by reducing carbon emissions, minimizing construction waste, and conserving resources. This research has significant implications for promoting the adoption of MMC globally, leading to more sustainable and efficient construction practices.