A myriad of industries is investigating and applying new technologies, approaches, and software to improve the systems engineering life cycle status quo, by reducing the time duration and lowering the cost incurred in the systems engineering process. One effort undertaken, and described herein, is pairing an Agile‐Lean framework with models‐based systems engineering (MBSE) to achieve time saving and cost efficiencies quickly within systems engineering concepts to production systems phases. This is being done by the Agile Processes and technologies (APT) team who are tasked to deliver a weapon prototype in three years. For this purpose, APT has adopted practices currently used in industry to speed up the conventional processes and practices within Los Alamos National Laboratory and partners, particularly by implementing Agile‐Lean within MBSE. APT has demonstrated agility by implementing changes at the organizational scale; given that most of the work done at the facilities is heavily based on design and hardware performance. In addition, MBSE is used to support verification and validation activities to drive acquisition of necessary evidence to establish traceability and compliance needed for qualification and certification, as per stakeholders' requirements. This paper describes the current efforts towards implementing MBSE in an Agile‐lean framework to represent a complex system —weapon prototype—, in a rapidly moving and changing environment to enable informed decisions through the identification and capture of useful decision criteria.