Sr. System Administrator

Location: Cerritos, CA (On site) | Type: Full Time | Salary Range: $95,000 a year Role Overview As Sr. Systems Administrator, you will serve as a technical anchor for our enterprise infrastructure spanning servers, cloud platforms, identity systems, networking, and security. You'll lead projects, mentor junior admins, drive automation, and be the escalation point for the environment's most complex problems. You will report directly to the IT Manager and will work alongside a team that values doing things right over doing things fast. Key Responsibilities Own and manage enterprise infrastructure across on-prem servers, cloud platforms, and core services Design, optimize, and maintain Windows Server environments, virtualization platforms (VMware / Hyper-V), and storage systems Ensure high availability, performance, and scalability across all systems and services Lead system upgrades, migrations, and platform improvements with minimal business disruption Manage and mature identity platforms including Active Directory, Microsoft Entra ID, SSO, and access controls Design and improve hybrid identity environments and Zero Trust / identity-first security architecture Implement and maintain secure configurations across servers, endpoints, and network boundaries Partner with our security team on vulnerability remediation, endpoint protection, and compliance initiatives Administer and tune security tooling: Sophos, Microsoft Defender, Proofpoint, and related platforms Build, maintain, and expand automation using PowerShell, Bash, or Python to reduce manual effort Standardize deployments, patching, and system configurations across 20+ locations Identify and eliminate operational inefficiencies; implement lasting improvements not workarounds Monitor systems, services, and infrastructure health using PRTG, PagerDuty, and related tooling Lead root cause analysis on complex incidents and implement durable long-term fixes Improve observability, alerting, and runbook coverage across the environment Lead infrastructure projects from design and planning through execution and documentation Partner with vendors, internal IT teams, and business stakeholders to deliver scalable solutions Collaborate cross-functionally to support application deployments and integration troubleshooting Mentor Systems Administrators and support staff; serve as a technical escalation point Define and enforce documentation standards, configuration baselines, and operational best practices Required Qualifications 5-8+ years of hands-on experience in Systems Administration or Infrastructure Engineering Expert-level proficiency with Windows Server environments and enterprise Active Directory Deep experience with Microsoft Azure, Microsoft Entra ID, and hybrid identity architectures Strong scripting and automation skills in PowerShell; Bash or Python a plus Virtualization experience with VMware and/or Hyper-V at scale Solid networking fundamentals: switching, VLANs, VPNs, firewalls, SD-WAN, and load balancing Proven experience with enterprise security tooling, endpoint protection, and patch management Experience with backup solutions, disaster recovery strategies, and high-availability design Familiarity with ITIL practices and enterprise monitoring/alerting platforms Strong analytical, troubleshooting, and written/verbal communication skills Preferred Qualifications Microsoft Certified: Azure Administrator Associate (AZ-104) Microsoft 365 Certified: Administrator Expert (MS-102) Experience with Cisco Meraki (switching, wireless, SD-WAN) Familiarity with Dealership Management Systems (Tekion, CDK, Reynolds, DealerBuilt) Experience implementing Zero Trust or identity-first security frameworks Background in multi-site enterprise environments (20+ locations preferred) What We Offer Medical, Dental, Vision, and Complimentary Life Insurance 401k Matching and FSA Tuition Reimbursement Paid Time Off (accrues) Supplemental Insurance (Hospital, Accident, Critical Illness) Discounts on Vehicles, Services, and Parts J-18808-Ljbffr