Senior IT Service Desk Engineer

About Castelion

Castelion is bringing a new approach to defense development and production: one that focuses on short, iterative design cycles, rapid testing in development, and modern commercial manufacturing strategies for production ’re designing, building, and testing next generation long range strike weapons systems to give America and its Allies a definitive edge and deter future conflicts.

We’re looking to hire a Senior IT Service Desk Engineer who thrives in fast‑paced, high‑pressure environments and brings strong technical acumen paired with a people‑first attitude. This role is ideal for individuals with experience supporting, engineering or aerospace firms, DoD contractors, or high‑growth startups. If you’re the kind of person who stays cool when things go down and can turn a stressful IT moment into a positive interaction, we want to meet you.

As the primary day‑to‑day support lead based out of our Torrance, CA office, you’ll be the face of IT for our local and remote teams. You’ll troubleshoot and document incoming issues, respond to employee requests with urgency and empathy, and help drive improvements in our support processes.

You’ll have every opportunity to flash your talent we need top‑tier self‑starters who love the energy and vibe of a focused, rapid‑paced company that’s working hard to impact their world.

• Serve as the primary support point for all end‑user IT issues (hardware, software, network, account access, etc.).
• Respond to, troubleshoot, and resolve service desk tickets in a timely and professional manner.
• Document all support cases clearly, including resolution steps, and proactively contribute high quality articles to our internal knowledge base.
• Support and maintain laptops, peripherals, and software in a 75% Windows / 25% Linux mixed environment.
• Act as the primary onsite support contact for the Torrance HQ office.
• Occasionally travel (5‑10%) to other sites (e.g., Allen, TX) to provide onsite IT support or assist with deployments.
• Identify and recommend process improvements to improve end‑user experience and operational efficiency.
• Help drive a culture of empathy and calm under pressure, improving team morale during high‑stress moments.
• Mentor or lead junior IT technicians if/when the team scales.

• 4+ years in a service desk or IT support role, with senior or lead‑level experience.
• Proven experience supporting engineering companies, DoD contractors, or fast‑paced, startup‑like environments.
• Exceptional troubleshooting skills across hardware, OS (Windows/Linux), mobile, VPN, and enterprise software suites (e.g., Office 365).
• Work tightly with a range of other IT and engineering departments to find efficiency gaps and push for solutions that will make a real impact & save people time.
• Excellent communication and interpersonal skills you make IT support feel like a positive experience.
• Able to prioritize tasks effectively and work independently under pressure.
• Comfortable managing multiple tasks or escalations in a dynamic setting.

• Experience working in or around SCIF environments or cleared facilities.
• Eligibility for clearance.
• Familiarity with device management (e.g., Microsoft Intune), asset inventory tracking, basic networking concepts, and user onboarding/offboarding workflows.
• Leadership aspirations or prior mentorship experience future supervisor potential is a big plus.

Desire and experience questioning assumptions in ways that lead to break through ideas that are ultimately implemented. Successfully bring in applicable processes/concepts/materials from other industries to achieve efficiency gains. The ability to personally resolve minor issues in development without requiring significant support.

A successful candidate will have a genuine passion for Castelion’s mission and consistently look for ways to contribute to the company’s technical goals and prevent hardware blockers. Ability to work in a fast paced, autonomously driven, and demanding atmosphere. Strong sense of…