Senior Network Engineer III Security Clearance

Position: Senior Network Engineer III with Security Clearance
Overview Millennium is proud to be part of the Markon Solutions family of companies a network of specialized organizations united in support of critical national security missions. This partnership strengthens our ability to deliver results by expanding our technical depth, operational reach, and access to a broader bench of proven experts, ensuring our customers continue to receive best-in-class cybersecurity support.

For more than two decades, Millennium has operated at the forefront of cybersecurity. Our elite team of over 300 professionals brings an unmatched record of performance across Red Team Operations, Defensive Cyber Operations, Software Engineering, and Technical Engineering. As home to the largest contingent of contracted Red Team operators supporting the Department of Defense, Millennium delivers unparalleled threat intelligence and battle-tested expertise to both DoD and federal civilian customers.

What We Believe Millennium is an equal opportunity employer and does not discriminate or allow discrimination on the basis of race, color, religion, gender, age, national origin, citizenship, disability, veteran status or any other classification protected by federal, state, or local law. Responsibilities Millennium is hiring a Network Engineer III to work onsite in Charleston, SC. The candidate must have an active Top Secret clearance.

The Network Engineer III will:
* Design, implement, and maintain secure and resilient network infrastructures supporting Marine Corps Information Technology (IT) systems under NIWC Atlantic's Expeditionary Enterprise Systems and Services (E2S2) Division.

* Configure, manage, and optimize network technologies, including Cisco SD-WAN, BGP, DMVPN/FlexVPN, HAIPE, and Multicast routing protocols.

* Support the integration of diverse network operating systems, hardware devices, and enterprise/tactical applications to ensure interoperability and mission readiness.

* Conduct network performance monitoring, troubleshooting, and capacity planning to ensure optimal uptime and reliability across environments.

* Develop and maintain network architecture documentation, configuration baselines, and implementation guides in compliance with DoD and NIWC standards.

* Collaborate with cross-functional engineering teams to design hybrid software, web, and hardware solutions from concept through deployment and sustainment.

* Ensure adherence to cybersecurity and information assurance requirements, supporting accreditation and risk management processes.

* Provide technical leadership and mentorship to junior engineers and support personnel, promoting knowledge sharing and best practices.

* Assist in project planning and execution, including defining scope, estimating costs, managing schedules, and addressing technical or operational challenges.

* Coordinate with external vendors and carriers (e.g., Verizon) to support connectivity, performance, and service-level agreements.

* Participate in regular engineering sync sessions and stakeholder reviews to report status, resolve issues, and align deliverables with mission objectives.

* Travel as required (up to 45 days annually) to support field installations, testing, and site sustainment. Qualifications
* Active Top Secret Clearance required.

* 7+ years of IT/network engineering experience.

* Hands-on experience with Marine Corps networks (enterprise and/or tactical environments).

* Proficiency in Cisco SD-WAN, BGP, DMVPN/FlexVPN, HAIPE devices, and Multicast technologies.

* Demonstrated ability to integrate diverse network operating systems, applications, and hardware across the full system lifecycle (design, coding, testing, and maintenance).

* Must obtain a professional or platform-specific certification within 12 months, such as:
* CCNP, CCDP, VCP, OCP, RHCP, or Microsoft role-based certifications (e.g., MCAD, MCDBA).

* Equivalent cloud or software engineering certifications may be accepted with COR approval. Business Development Assist with Business Development activities as required to support Millennium's strategic business objectives, which may include but not limited to participation in technical interviews, creation of technical documentation, general proposal writing support and proposal color reviews.

Physical Requirements
* Must be comfortable with prolonged periods of sitting at a desk and working on a computer.
* Must be able to lift up to 10-15 pounds at a time.