Senior ISSR: TS Cybersecurity RMF & ATO Lead

3M HEALTHCARE; Arlington (VA); On-site; USD 113,000 - 188,000; Full time

Job summary

Guidehouse seeks a Senior Information System Security Representative (ISSR) to support a major federal mission. The role ensures controlled systems are authorized, operated, and maintained in compliance with NIST RMF and SAA requirements, working with system owners, ISSOs, ISSEs, assessors, and Authorizing Officials.

Responsibilities include leading the SAA/ATO process, guiding on baseline controls, and coordinating assessment activities to deliver complete SAA/ATO packages and maintain

Qualifications

• Bachelor’s degree in cybersecurity, information systems, computer engineering, or related field.
• Ten years of professional IT or cybersecurity experience with senior responsibilities.
• Seven years of ISSR or A&A/SAA experience in cleared federal environments.
• ACTIVE and CURRENT TOP SECRET clearance.
• Strong understanding of NIST RMF, SAA/ATO, and security governance.
• Ability to collaborate with Authorizing Officials and diverse teams.

Responsibilities

• Ensure controlled systems operate per approved SAA/ATO requirements and policies.
• Lead and manage the SAA process for new and legacy systems.
• Guide system owners on baseline controls, categorizations, and authorization boundaries.
• Provide recommendations on classifications, boundaries, and residual risk.
• Maintain and coordinate SSPs, MOUs, and MOAs for interconnections.
• Coordinate assessment activities with assessment teams and Officials.
• Prepare and submit complete SAA/ATO packages for executive decisions.
• Track ATO documentation in agency tracking systems (e.g., Sentinel).
• Advise on vulnerabilities and remediation actions.
• Oversee POA&M management and re-testing.
• Coordinate reauthorization after major changes or incidents.

Skills

RMF lifecycle execution

Security governance

NIST SP 800-53 Rev.5

Top Secret clearance

Leadership

Communication

Education

Bachelor’s degree in Cybersecurity/Information Systems/Computer Engineering

Tools

Sentinel (GRC tool)

Job description

Guidehouse seeks a Senior Information System Security Representative (ISSR) to support a major federal mission. The role ensures controlled systems are authorized, operated, and maintained in compliance with NIST RMF and SAA requirements, working with system owners, ISSOs, ISSEs, assessors, and Authorizing Officials.

Responsibilities include leading the SAA/ATO process, guiding on baseline controls, and coordinating assessment activities to deliver complete SAA/ATO packages and maintain