MANTECH seeks a mission-focused Cybersecurity System Security Engineer III to support Special Access Programs (SAPs) aligned with SSC and AFSPC acquisition initiatives. In this on-site role located in El Segundo, CA , you will work closely with security professionals to safeguard vital national security systems while ensuring compliance with NIST, DoD, and SAP cybersecurity frameworks.

Responsibilities include but are not limited to:

You will lead advanced system security engineering initiatives, helping ensure that acquisition systems meet security and accreditation requirements from design through deployment. Lead a team of System Security Engineers and Certification & Accreditation Analysts responsible for safeguarding U.S. and allied national security interests. Provide technical direction, policy alignment, and oversight during system design, development, and testing phases. Chair or co-chair cybersecurity working groups, represent the Government Program Manager in advisory bodies, and actively participate in SSE IPTs to ensure integration of security across SAP systems. Guide the development, implementation, and evaluation of cybersecurity policies. Oversee integration of SAP network infrastructures and provide expert-level consultation across all aspects of information security. Review and assess secure system designs, providing risk management recommendations to stakeholders. Ensure compliance with RMF, JSIG, and other relevant accreditation processes. Support Mission and Training system development with SSE expertise, including review of system architectures, test and evaluation events, and overall security engineering input throughout the acquisition lifecycle. Assist in the development and ongoing maintenance of Program Protection Plans and Cybersecurity Strategies. Support site activations and major security review events. Collaborate directly with accreditation authorities to guide systems toward Authorization to Operate (ATO), while managing documentation and continuous compliance throughout system operation.

Minimum Qualifications: Bachelor’s degree in a related discipline; An additional 4 years of related experience might be substituted for a degree 12 + years of relevant experience 8 + years supporting SCI or SAR environments Must meet position and certification requirements outlined in DoD Directive 8570.01-M for Information Assurance Technician Level 3 and Information Assurance Manager Level 3 within 6 months of the date of hire. CISSP Recommended. Strong understanding of RMF and JSIG accreditation processes, as well as legacy frameworks such as DITSCAP and DIACAP

Preferred Qualifications: Familiarity with key security directives including ICDs, JAFANs, and DoD Manuals 4 + years of SAP-relevant experience

Clearance Requirements: Current TS/SCI clearance Must be eligible for access to Special Access Programs. Willingness to submit to a Counterintelligence polygraph is required.

Physical Requirements: Willingness to travel within the organizational Area of Responsibility (AOR), including air and ground transport as needed Must be able to remain in a stationary position approximately 50% of the time using standard or adjustable desks/chairs in secure environments Occasionally required to move about the office to access safes, files, and technical equipment, and may assist with the installation or removal of computer components