Senior System Administrator

• Radiant is seeking a Senior Systems Administrator to own the systems that keep the company running day-to-day within Microsoft 365 GCC High
• You’ll own the tenant, build our identity and access automation from the ground up in an Entra-native environment with no on-prem Active Directory or Group Policy, and manage the endpoint, email security, and SaaS infrastructure the business runs on
• You’ll implement and evidence the technical controls behind our CMMC assessment as part of the normal job, not a detour
• This is a high-ownership seat in an interdisciplinary environment, advancing milestones toward commercializing the first mass-produced nuclear reactor
• Own Microsoft 365 GCC High: Exchange Online, SharePoint, Teams, and the tenant configuration underneath them; be the authority on what’s possible in this cloud and what has to be built in-house
• Own Entra end-to-end: conditional access, privileged access, app registrations, and single sign-on
• Build the IAM automation layer, the centerpiece of the role: joiner/mover/leaver lifecycle, entitlements driven by HR data, provisioning through Graph and SCIM, and access reviews that run themselves
• Own Windows and endpoint management through Intune, Autopilot, compliance policy, and update rings across the fleet, with no Group Policy underneath
• Own email security and information protection: Defender for Office, mail flow and anti-phishing posture, and Purview for DLP, labeling, and retention in an environment handling CUI
• Own SaaS administration and integration across the business application portfolio, including Box and Slack; some running today, some a project waiting for an owner
• Own the workloads, services, and licensing infrastructure running in AWS, in constant contact with the IT DevOps engineer who owns the account layer
• Take new platform projects from idea to deployed, integrated, and documented
• Implement and evidence the technical controls in these areas for the CMMC assessment ahead, as normal work rather than a detour

Benefits

• Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans
• Equity: Substantial incentive stock plan for all salaried employees
• Dental: 100% coverage, orthodontia extra, 50% for dependent
• Flexible PTO policy
• Vision: 100% coverage + 50% for dependents
• Voluntary Life, Accident, Hospital, Critical Illness, Commuter and FSA are offered as employee contributed benefits
• Beautiful El Segundo headquarters close to the Pacific Ocean
• Team-bonding company outings, happy hours and in-person camaraderie

• Deep, hands-on experience across the responsibilities above: GCC High tenant administration, Entra, self-built IAM automation, Intune without Group Policy, email security and Purview, and SaaS/AWS administration
• Service is the job; tier-1 handles day-to-day support, but nobody’s too senior to help the person at their desk
• 7+ years administering and engineering production systems
• Bachelor’s degree in Information Technology, Computer Engineering, Cybersecurity, or a similar field (4 years of work experience in lieu of a degree)
• Solid networking fundamentals: VLANs, routing, firewall policy, DNS/DHCP, VPN, wireless
• Treats compliance control implementation and evidence collection as normal work
• Must be willing to work extended hours and weekends as necessary to accomplish our mission
• Deployed Box, Slack, or comparable platforms into a regulated environment and handled the data boundary questions
• Purview depth: DLP, sensitivity labeling, retention, or eDiscovery
• Automation experience with PowerShell, Python, Microsoft Graph, and infrastructure as code (Terraform, Bicep, or similar)
• Written and maintained PowerShell modules other people use, not just scripts
• CMMC or NIST 800-171 exposure; leading an assessment is not required
• Stood up identity governance tooling: Entra ID Governance, SailPoint, Okta Workflows, or equivalent