Lead Network Engineer with Security Clearance

Overview Millennium is proud to be part of the Markon enterprise, 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 Lead Network Engineer in Arlington, VA. Qualified candidates must have an active TS/SCI.    The Lead Network Engineer serves as a designated Key Personnel for a Federal Civilian Agency.  This senior-level subject-matter expert is responsible for the architecture, engineering design, testing, implementation, and integrity of the Agency's enterprise-wide network infrastructure, including Wide Area Network (WAN), Local Area Network (LAN), Software-Defined Networking (SDN), cloud interconnectivity, Domain Name System (DNS), wireless, and related enterprise network tools in both on-premises and cloud environments (commercial, private, and hybrid). * Serve as the primary technical authority for all network engineering, design, testing, deployment, and Tier-3 escalation support across the enterprise, cloud, and hybrid environments. * Lead the development and maintenance of System Design Documents (SDDs), Detailed Design Documents (DDDs), Technical Requirements Documents (TRDs), test plans, implementation plans, and transition artifacts in accordance with ITIL v3 (v4) frameworks. * Engineer and implement secure, high-performance network connectivity to commercial cloud service providers (CSPs), private cloud, and hybrid cloud environments. * Design, test, and deploy enterprise network technologies including but not limited to identity and access management integration, SDN, zero-trust architectures, IPv6, and next-generation firewall solutions. * Provide expert-level troubleshooting and resolution of complex network, cloud interconnectivity, and performance issues. * Conduct hardware/software testing in lab environments, evaluate vendor-recommended patches/fixes, and ensure compatibility and security before production deployment. * Lead Change Request preparation, presentation at technical review boards, and coordination of network changes to minimize mission disruption. * Mentor junior engineers and collaborate closely with the Lead Enterprise Architect, cloud engineers, cybersecurity teams, and IT Operations. * Ensure all designs and implementations fully comply with Agency, NIST SP 800-53 Rev 4/5, FedRAMP, FIPS 140-2, Section 508, and HLS EA requirements . Qualifications * Have an active TS/SCI clearance. * Bachelor’s degree in Engineering, Computer Science, Information Systems, or a related technical discipline. * Minimum 10 years of progressive experience in network engineering and design. * Certified in Cisco CCIE (Routing & Switching or Enterprise Infrastructure) Cisco CCDE Juniper JNCIE-ENT or JNCIE-SP Palo Alto Networks PCNSE or PCCSE AWS Certified Advanced Networking – Specialty Azure Network Engineer Associate ITIL v3 or v4 Foundation   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.