Senior Systems Engineer - Cyber Systems

We are seeking a Senior Systems Engineer - Cyber Systems to support a high-priority program through system security engineering, cybersecurity architecture implementation, RMF execution, and mission assurance activities in a secure customer environment. This role is best suited for a senior systems engineer who can operate independently in a complex, high-consequence setting; assess and improve system security posture; and work across engineering, program, and leadership teams to support compliance, execution, and technical risk reduction.

What you’ll do

• Lead cyber systems engineering activities related to security controls, technical baselines, architecture implementation, and compliance posture for assigned program efforts.
• Design, plan, implement, and assess security controls, policies, and processes in alignment with program requirements and applicable security frameworks.
• Support implementation of system security architectures and integration of cyber requirements into the broader system development lifecycle.
• Analyze cyber infrastructure challenges, identify technical risks, and develop engineering solutions responsive to customer and mission needs.
• Execute RMF-related activities, including documentation, assessment support, POA&M management, and accreditation lifecycle support.
• Assess system security posture and communicate findings, risks, and recommendations to engineering teams, program leadership, and stakeholders.
• Participate in technical reviews of requirements, design, and implementation plans prior to deployment.
• Support ATO-related activities and broader mission assurance objectives through disciplined security engineering execution.
• Interface with cyber functional teams, internal leadership, and executives to support effective program execution.

Do you have experience in System security?, Do you have a Master’s degree?, * Bachelor’s degree in a STEM discipline with 12 years of relevant experience, or Master’s degree in a STEM discipline with 10 years of relevant experience, or PhD with 8 years of relevant experience.

• Active TS/SCI clearance with Full Scope Polygraph required at time of application.
• Current DoD IAT Level II Security+ certification.
• Current DoD 8570 IAM Level III certification, such as CISSP, CISM, or equivalent.
• 10+ years of relevant experience in systems security engineering, cyber engineering, or security-focused systems integration in complex technical environments.
• Experience with DoD System Security Engineering activities.
• Strong knowledge of RMF, NIST 800-37, NIST 800-53, STIGs, and requirements development from control listings.
• Experience supporting ATO attainment and accreditation activities, including documentation, scanning, assessment support, and POA&M management.
• Experience assessing system security posture against customer requirements and directives.
• Strong ability to coordinate across cyber teams, engineering teams, program leadership, and executive stakeholders in support of mission assurance and effective program execution.
• Strong written and verbal communication skills., * Experience planning, configuring, installing, operating, and maintaining enterprise security tools such as Splunk, Rapid7, Trellix, and related SQL database environments.
• Experience implementing or sustaining SIEM/SOAR capabilities in secure or mission-critical environments.
• Experience adapting commercial security methodologies and technologies within sensitive or proprietary customer environments.
• Experience integrating cyber systems engineering requirements into the System Development Life Cycle (SDLC).
• Experience translating implementation requirements into JIRA tasks or similar agile work-tracking mechanisms.
• Experience with automation techniques for deployment into new environments, such as Ansible.
• Experience configuring and deploying Cross Domain Solutions (CDS).
• Experience supporting multidisciplinary engineering teams and contributing to technical proposals.
• Experience in defense, intelligence, or other highly secure customer environments with complex compliance and mission constraints.

Pulled from the full job description

• Retirement plan
• Paid time off
• Vision insurance
• Dental insurance
• Disability insurance
• Employee stock ownership plan, Salary: The salary range for this role is $193,700.00 - $262,000.00 per year. The salary range provided is a good faith estimate representative of all experience levels. Four Sea Group, Inc. considers several factors when extending an offer, including but not limited to, the role, function and associated responsibilities, a candidate’s work experience, location, education/training, key skills, and market conditions.

Application Deadline: This position is expected to remain open through June 19, 2026. The company may adjust this deadline based on business needs and will update the posting as appropriate.

Benefits: FSG is 100% ESOP-owned, which means our employees share directly in the company’s growth. We offer competitive compensation, a strong employer-funded retirement plan, generous PTO and flexible time-off options, comprehensive health, dental, vision, life, short-term disability, and long-term disability benefits, plus a generous medical stipend that gives employees more choice and flexibility. Our model is intentionally built to keep more value with employees through salary, retirement, benefits, and ownership. You will work alongside experienced engineers and technical leaders on meaningful defense, space, software, systems, and mission support work, with room to grow as a technical expert, mentor, program contributor, or future leader.

Four Sea Group is a 100% employee-owned technical mission support company based in Denver, Colorado. Founded by an aerospace industry veteran and PhD astrophysicist, we support complex defense, space, software, systems, and mission-focused programs for government and industry partners. What sets FSG apart is the caliber of our people and the way we operate: we are a reputation-driven team of highly skilled engineers and technical experts who are brought in for their depth, judgment, and ability to solve difficult problems. As an employee-owned company, we have built our compensation, benefits, and culture around a simple idea: when the company succeeds, that value should go back to the people doing the work.