Senior ISSE (TS/SCI w/ Full-Scope Poly)

Agentic Defense Solutions, Inc.; Tysons (VA); Hybrid; USD 140,000 - 210,000; Full time

Job summary

Agentic Defense Solutions, Inc. is seeking a Principal Information Systems Security Engineer to be the senior technical authority for security engineering across mission systems at multiple classification levels.

This hands-on role involves owning security architecture from concept to accreditation, translating policy into engineering requirements, and interfacing with the AO, SCA, ISSM, and customer stakeholders.

Qualifications

• Active TS/SCI with Full Scope Polygraph.
• 15+ years of information security engineering experience in classified environments.
• Minimum 10 years of ISSE experience in classified settings.
• Proven ownership of at least three systems through full ATO.
• Deep knowledge of NIST SP 800-53, NIST RMF, CNSSI 1253, ICD 503, DISA STIG/SRG.

Responsibilities

• Lead security architecture and design for mission systems across on-prem, air-gapped, and cloud regions.
• Own the full accreditation lifecycle under NIST RMF and ICD 503, including SSP, SAR, POA&M.
• Interface with AO, SCA, ISSM and government stakeholders to present risk positions.
• Perform threat modeling, architecture reviews, and design trade studies; document residual risk.
• Engineer and validate control implementations against NIST SP 800-53 and CNSSI 1253; drive automated compliance.
• Mentor ISSEs, ISSOs, and system engineers; develop reusable patterns and standards.
• Support capture and proposals as security SME; contribute to technical volume and architecture.

Skills

Active TS/SCI with Full Scope Polygrap

15+ years experience

10+ years ISSE in classified env

Full ATO ownership

Clear communication of risk to govt

Tools

Linux

NIST SP 800-53

NIST RMF

CNSSI 1253

AWS

Azure

DISA STIG/SRG

Job description

Agentic Defense Solutions, Inc. is seeking a Principal Information Systems Security Engineer to be the senior technical authority for security engineering across mission systems at multiple classification levels.

This hands-on role involves owning security architecture from concept to accreditation, translating policy into engineering requirements, and interfacing with the AO, SCA, ISSM, and customer stakeholders.