Why Castelion, Why Now

Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus and technical excellence are decisive advantages - and we are building a team that can deliver real capability, not just concepts.

This is a rare opportunity to join at an early stage, where your work will directly shape critical systems, influence major technical decisions, and have immediate, real-world impact.

Senior Manager, Classified Networks Administration

Build, scale, and lead enterprise classified IT infrastructure across multiple secure facilities. Own strategy, architecture, deployment, and operations of classified network environments supporting mission-critical defense programs. Partner closely with Engineering, Cybersecurity, Facilities, Security, and Program Management to deliver compliant, resilient infrastructure in a fast-paced defense startup.

Key Responsibilities

• Define and execute enterprise classified network strategy across multiple sites, labs, and manufacturing facilities.
• Design, implement, and operate infrastructure supporting Secret, Top Secret, SCI, and SAP environments.
• Oversee networking, compute, virtualization, storage, identity management, monitoring, and disaster recovery.
• Ensure compliance with RMF, NIST 800-53, ICD 503, DISA STIGs, and Zero Trust principles; support ATOs and government accreditation activities.
• Drive infrastructure modernization through automation, Infrastructure as Code, and DevSecOps practices.
• Partner with engineering, program management, and executive leadership to align technology delivery with business growth.
• Manage infrastructure budgets, vendor relationships, and multi-year technology roadmaps.
• Recruit, develop, and retain high-performing technical talent across multiple locations.
• Support new facility stand-ups, classified program starts, and proposal activities.

Required Qualifications

• Bachelor's degree in Computer Science, IT, Engineering, or related field.
• 10+ years designing and operating enterprise infrastructure in classified environments.
• 5+ years leading technical teams across multiple sites.
• Experience in a defense contractor or government environment.
• Strong working knowledge of NIST SP 800-53, RMF, DoD cybersecurity policy, Windows Server/AD, Linux, VMware, Cisco networking, and enterprise storage.
• Demonstrated success building and scaling IT organizations in high-growth settings.
• Active Top Secret clearance; SCI eligibility required (CI Poly preferred). U.S. citizenship required.

Preferred Qualifications

• SAP and SCI environment experience.
• SCIF or classified facility stand-up experience.
• Automation proficiency: PowerShell, Python, Terraform, or Ansible.
• Familiarity with Azure Government, AWS GovCloud, or hybrid classified cloud environments.
• Certifications: CISSP, CCNP/CCIE, VMware VCP, Azure Administrator, or equivalent.

What You'll Accomplish in Year One

• Establish scalable classified network infrastructure supporting multiple DoD programs.
• Achieve or maintain ATOs for critical classified systems.
• Build and develop a high-performing classified IT team.
• Develop repeatable operational processes that support rapid company growth.

Additional Requirements:

• Ability to put in extended hours, including evenings and weekends, when required to meet aggressive timelines
• This role is based in Torrance, CA and requires full-time onsite presence

Other Duties

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice.

Benefits And Perks

All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory. We offer four (4) weeks of paid time off, ten (10) company-paid holidays, and comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans. We also provide paid parental leave to support growing families, a $100 monthly fitness stipend to promote health and performance, and onsite EV charging for convenience. In addition, employees enjoy perks like catered meals, company-covered food during high-demand periods, and a fully stocked kitchen to stay fueled throughout the day.

While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government– issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.

Affirmative Action/EEO Statement

Employment with Castelion is governed on the basis of competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.