Information System Security Officer (ISSO), Senior (On-Prem & Cloud)

AMERICAN SYSTEMS is seeking a Senior Information System Security Officer (ISSO) to manage RMF execution, authorization, and continuous monitoring for hybrid on‑premises and cloud systems supporting classified government missions in Chantilly, VA.

This role is ideally suited for a security leader who is detail‑oriented, highly organized, and confident guiding system owners and engineers through RMF execution, authorization decisions, and ongoing compliance in classified environments.

As an AMERICAN SYSTEMS Senior ISSO, you will:

• Lead RMF execution for assigned systems from categorization through continuous monitoring.
• Maintain ICD 503 and FIPS 199 security artifacts supporting system authorization.
• Develop, update, and manage ATO packages and authorization documentation.
• Conduct or oversee daily audit log reviews for anomalous activity and report findings to the Government as soon as practical.
• Coordinate risk assessments and remediation activities with engineering teams.
• Enforce security policies and ensure ongoing compliance throughout the system lifecycle.
• Serve as the primary point of contact for security reporting to the COTR, CO, and Government security authorities.
• Support audits, inspections, reciprocity efforts, and CORA activities.
• Support Privileged User Program and IA Workforce reporting requirements.

• Active TS/SCI clearance and current polygraph (required to be considered)
• Bachelor’s degree in Cybersecurity, Information Assurance, or a related STEM field
• 10+ years of experience in RMF execution, cybersecurity compliance, and governance
• DoD 8570/8140 IAM Level III certification (e.g., CISSP, CISM, or CCSP)
• Experience managing ATO packages and supporting continuous monitoring
• Exposure to and understanding of hardening cloud assets
• Strong working knowledge of ICD 503, NIST SP 800‑53, and FIPS 199.
• Experience coordinating risk remediation across technical and operational teams.