Senior Systems Administrator

The Nuclear Company is the fastest growing AI tech-enabled startup in the nuclear and energy space, pioneering a fleet-scale approach to building the next generation of nuclear reactors. Through our design-once, build-many model, we're accelerating the deployment of safe, reliable, and affordable nuclear energy.

We operate with an AI-first mindset. Every employee is expected to leverage AI, technology, and the Nuclear Operating System (NOS) as integral components of their role to improve the quality, speed, and impact of their work. We expect every team member to continuously identify opportunities to automate workflows, enhance decision-making, improve processes, and contribute to the ongoing evolution of NOS as a strategic operating capability that enables The Nuclear Company to scale with excellence.

We hire people who are driven by purpose, thrive in ambiguity, and are energized by building what has never been built before. Our team combines intellectual curiosity with high agency, embraces candid feedback and continuous learning, and holds themselves and others to exceptional standards. Our values—
Transparency, Responsibility, Unity, Scrappy, and Tenacity
—guide how we hire, collaborate, and make decisions every day. They are not words on a wall; they are the standard by which we operate. TRUST is the foundation of our safety culture, fostering intellectual honesty, accountability, and open communication, while our values challenge every team member to execute with urgency, humility, resilience, and an unwavering commitment to our mission.

The Nuclear Company is seeking a Senior Systems Administrator to securely administer and scale Microsoft 365, Microsoft Entra , managed endpoints, AWS, and Windows/Linux server environments. This role serves as the primary administrator and Tier 3 escalation point for assigned platforms, remediates legacy configuration risks, and builds automation that makes provisioning, compliance evidence, and reporting repeatable. The Senior Systems Administrator partners with Infrastructure, Cybersecurity, HR, Legal, and Engineering to maintain reliable, auditable services and support the organization's compliance and audit-readiness objectives.

The ideal candidate is a hands‑on technical professional with a security‑first mindset who moves effectively in a fast‑paced environment and automates high‑value, repeatable work.

• Administer and securely scale Microsoft 365, including Exchange Online, SharePoint Online, mail flow, retention, sharing, and licensing.
• Administer Microsoft Entra , SSO, MFA, Conditional Access, role-based access control, privileged access, and user lifecycle processes.
• Audit user and administrator accounts, security groups, roles, and licenses; remediate orphaned identities, excessive access, and legacy configuration issues.
• Configure and operate assigned DLP and insider-risk technical controls in partnership with Cybersecurity and Legal and in accordance with approved policies and applicable requirements.

• Standardize enrollment and compliance through Intune across Windows, macOS, and iOS, and use Ninja One or another approved RMM platform for supported endpoint monitoring and management.
• Maintain device naming, security baselines, configuration policies, patching, software deployment, inventory accuracy, and remediation workflows.
• Support the complete device lifecycle, including onboarding, refresh, reassignment, and secure offboarding.

• Administer and maintain Microsoft Azure and AWS environments, with Azure serving as a primary enterprise platform. Establish scalable standards across both platforms for identity and access management, security configuration, logging, monitoring, backup, and recovery to support current operations and future growth.
• Administer Windows Server and Linux environments, including Active Directory, Group Policy, DNS, DHCP, system hardening, patching, and operational monitoring.
• Maintain system backup and recovery procedures, perform documented restoration tests, and support execution of…