Information System Security Engineer (ISSO) / IT Systems Engineer

Arlington, United States | Posted on 05/26/2026 We are seeking an experienced Information System Security Engineer (ISSO) / IT Systems Engineer to serve as the Classified Information Security Lead for the organization. This Arlington‑based role is responsible for managing and safeguarding Secret and Top‑Secret information across diverse research and operational environments. Candidates must be U.S. citizens with an active Top Secret (TS) clearance and SCI eligibility . Role Responsibilities Serve as the primary lead for classified information security , ensuring full compliance with federal regulations governing the handling, storage, transmission, and protection of national security information. Maintain the security posture of classified and unclassified systems , including configuration, monitoring, and continuous improvement. Oversee cybersecurity compliance , documentation, and accreditation artifacts (e.g., security plans, risk assessments, POA&Ms). Execute contract‑specific security duties supporting legal proceedings, research operations, and government‑sponsored programs. Support research environments spanning multiple sponsors, classification compartments, and non‑standard computing environments . Work closely with end users, program managers, and sponsors to meet contract milestones, address technical needs, and support new proposals and project launches. Requirements U.S. citizenship with an active TS clearance and SCI eligibility Strong understanding of federal regulations governing classified information (e.g., NISPOM, ICDs, RMF) Experience maintaining the security posture of classified and unclassified systems Proficiency with cybersecurity compliance , documentation, and system accreditation Ability to support diverse research environments, including non‑standard or specialized computing setups Strong communication, problem‑solving, and stakeholder‑coordination skills Ability to balance end‑user needs, sponsor requirements, and contract timelines in a fast‑moving environment You will serve as the lead authority for classified information security across a mission‑driven organization. You will work directly with high‑impact research programs , legal operations, and government‑sponsored initiatives. You will shape and maintain secure environments across multiple classification levels and technical architectures. You will play a critical role in enabling new research, proposals, and project execution while ensuring full compliance. #J-18808-Ljbffr