We are hiring a Principal Systems Engineer with an active TS/SCI clearance to support our government customer in Springfield, VA. This position is 100% on-site and requires the ability to obtain and maintain a Polygraph. The Senior-level Principal Systems Engineer will lead a diverse, multi-disciplinary team of Information Technology engineers to tackle complex, enterprise-level challenges. This role supports the organization's Architecture & Engineering (A&E) team and is responsible for driving end-to-end engineering activities that impact mission systems, enterprise services, and modernization initiatives. The Principal Systems Engineer will oversee system integration, requirements engineering, performance analysis, testing and evaluation, and lifecycle management to deliver secure, resilient, and scalable IT capabilities that directly support mission and business objectives.