The need to include sustainable design principles during product realization poses several challenges in need of research. The demand for greener products has increased while competition has shortened product realization processes. Product Lifecycle Management (PLM) provides solutions in accelerating the development process and time to market by managing the information through a full life cycle of a product line. Life Cycle Assessment (LCA) provides a way to predict the environmental impacts that should be expected over the complete life cycle of a given product, but LCA methods are not well suited to efficient comparison of product alternatives during early design stages. Customers and other stakeholders demand products that not only comply with regulations and minimize environmental impacts, but also minimize costs and maximize certain performance objectives of a product. Thus, an approach is needed to unify validation of new products compliance with holistic consideration of environmental impacts along with other objectives over a complete life cycle for the selection of the optimal design concept in an efficient manner. This research addresses these matters by proposing the approach of integrating LCA software with a PLM system. A conceptual LCA framework- LCAatPLM (Life Cycle Assessment of assembly tree in PLM) is proposed that allows environmental assessment of assembly tree directly extracted from PLM. Firstly, relevant existing solutions are reviewed and several challenges are identified that prevent integration. By decomposing the structure of both PLM and LCA, a common foundation is identified for the integration. Then, a design methodology is developed to show the use of LCAatPLM within PLM environment. A charcoal grill design case study is detailed to show how evaluations can be made based on achievement of strategic goals, along with verification of compliance and the visibility of LCA and other results. Our findings show that design executions through LCA integrated with PLM reveal environmental criterion at early stages. It can be considered with other design criteria to identify and select optimal alternatives. This research transforms LCA as an evaluation tool used after a design is already completed to one that can guide designs earlier within the PLM environment.