Cybersecurity Lead - Information System Security Manager; ISSM

Cybersecurity Lead/Information System Security Manager (ISSM)

Sphinx is hiring a Cybersecurity Lead/Information System Security Manager (ISSM) to join our growing team and support the delivery of secure software and systems for next-generation space and defense programs. This role is ideal for a cybersecurity professional with deep experience navigating classified environments, managing Risk Management Framework (RMF) activities, and driving successful authorization efforts across complex government systems.

The ISSM will lead security and compliance efforts across assigned programs, partner closely with software engineering teams, and coordinate with government stakeholders to achieve and maintain system approvals and accreditations. You'll play a critical role in ensuring our mission systems meet security requirements, maintain compliance, and successfully achieve and sustain authorization across classified environments.

In this role, you'll work closely with Program Leadership, Engineering, Dev Ops, and government security representatives to build, secure, and sustain systems supporting national security missions.

What you will be focusing on:

• Leading cybersecurity efforts across assigned programs, ensuring systems meet government security requirements and accreditation objectives.
• Managing RMF activities throughout the system lifecycle, including authorization packages, security documentation, assessments, and continuous monitoring activities.
• Leading cybersecurity compliance efforts and coordinating with engineering, program, and government stakeholders to support successful authorization, accreditation, and ongoing security operations.
• Partnering with Software Architects and engineering teams to integrate security requirements into system design and implementation.
• Preparing, reviewing, and maintaining cybersecurity artifacts, plans, reports, and executive briefings.
• Supporting security assessments, audits, inspections, and government reviews.
• Identifying security risks, vulnerabilities, and compliance gaps while driving effective mitigation strategies.
• Coordinating cybersecurity incident response activities, including investigation, containment, remediation, reporting, and communication with internal stakeholders, customers, and government representatives as required.
• Collaborating with government Authorizing Officials (AOs), Security Control Assessors (SCAs), and customer security representatives to obtain and maintain system authorizations.
• Contributing to the development and improvement of cybersecurity policies, processes, and best practices across the organization.
• Staying current on evolving cybersecurity requirements, threats, and industry best practices impacting classified environments.

You might be a good fit if you:

• Have 7+ years of experience in cybersecurity, information assurance, information system security, RMF, or related security disciplines.
• Have 5+ years of experience supporting classified programs and secure government environments.
• Have 5+ years of experience with cybersecurity, compliance, and vulnerability management tools supporting accreditation and continuous monitoring activities.
• Have 5+ years of experience assessing, analyzing, and documenting security test results, compliance evidence, and technical findings to support authorization and accreditation efforts.
• Have experience serving as an ISSM, ISSO, ISSE, or similar cybersecurity leadership role supporting classified government programs.
• Possess strong working knowledge of the Risk Management Framework (RMF) and associated guidance, including NIST 800-series publications, JSIG, ICD 503, CNSSI 1253, or equivalent frameworks.
• Have experience developing and managing authorization packages and supporting Authority to Operate (ATO) efforts.
• Have experience reviewing subcontractor security postures, validating external compliance and authorization artifacts, and establishing Interconnection Security Agreements (ISAs) to support secure data exchange across corporate, customer, and network boundaries.
• Are comfortable leading security compliance activities, audits, assessments, and continuous monitoring programs.
• Have experience working closely with software development and systems engineering teams in secure environments, including maintaining subcontractor coordination across multiple security and network environments.
• Hold a current IAM Level III certification or equivalent certification such as CISSP, CISM, or GSLC.
• Have experience using cybersecurity tools and technologies such as ACAS, Nessus, SCAP, STIGs, audit reduction tools, or similar compliance and vulnerability management platforms.
• Possess strong written and verbal communication skills with the ability to engage technical and non-technical stakeholders.
• Hold an active Secret clearance and be eligible to obtain and maintain TS/SCI access. Active TS/SCI clearance is preferred.

Bonus points if you:

• Have experience supporting space, intelligence community, or Department of Defense programs.
• Have…