Senior Systems Administrator

# Senior Systems Administrator Torrance, CA 90503## Overview Salary Range$ - $ Salary## Description##
** Position Summary**---The Senior Systems Administrator will own the reliability, security, and performance of critical IT infrastructure across Microsoft 365, cloud, on-premises, endpoint, identity, and collaboration platforms. This role is ideal for a hands-on infrastructure professional who can operate independently, solve complex technical issues, improve system resiliency, and help mature IT operations in a secure, compliance-focused environment.

The Senior Systems Administrator will support both daily operations and strategic infrastructure initiatives, including Microsoft GCC High and Commercial environments, Windows/Linux server administration, Azure and AWS services, endpoint support, automation, patching, monitoring, backups, incident response, documentation, and service management.

This individual will also serve as a technical escalation point and mentor for other IT team members.

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** Essential Duties and Responsibilities**--
- ** Systems, Infrastructure, and Platform Administration
*** Administer, maintain, and optimize Windows, Linux, and macOS systems across endpoint, server, and cloud-hosted environments.
* Manage on-premises and cloud-based servers, including provisioning, configuration, patching, monitoring, backup validation, lifecycle management, and decommissioning.
* Support Microsoft 365 environments, including Microsoft GCC High and Microsoft Commercial tenants, with a focus on availability, security, identity, access, and user productivity.
* Administer core infrastructure services such as Active Directory, Entra /Azure AD, DNS, DHCP, Group Policy, file services, print services, certificates, and related enterprise services.
* Support Azure and AWS infrastructure, including virtual machines, storage, networking, access controls, monitoring, and cost-conscious operational practices.
* Maintain and improve system monitoring, alerting, logging, capacity planning, and performance management across business-critical infrastructure.
** Security, Compliance, and Reliability
*** Implement and maintain secure configuration baselines, patching standards, vulnerability remediation processes, and access control practices.
* Support security and compliance requirements for controlled or sensitive environments, including Microsoft GCC High, privileged access, audit logging, evidence collection, and change control.
* Participate in incident response, root-cause analysis, corrective action planning, and post-incident improvement activities.
* Ensure backup jobs, restore procedures, disaster recovery plans, and business continuity processes are documented, tested, and improved over time.
* Partner with security, engineering, and business stakeholders to reduce operational risk while maintaining usability and system performance.
** Service Management, Support, and Documentation
*** Serve as a senior escalation point for complex infrastructure, endpoint, identity, cloud, and application issues.
* Manage incidents, service requests, changes, and problem records using Jira and Jira Service Management.
* Create and maintain technical documentation, standard operating procedures, runbooks, diagrams, and knowledge-base articles in Confluence.
* Track infrastructure projects, operational tasks, and cross-functional work using tools such as Smartsheet, Jira, and Confluence.
* Communicate clearly with technical and non-technical stakeholders regarding outages, maintenance windows, risks, project status, and recommended solutions.
** Application and Engineering Tool Support
*** Support enterprise tools and infrastructure integrations, including Adobe Acrobat, Solid Works PDM, Git Lab, Git Hub, and Jenkins Build Server where applicable.
* Assist with access management, server dependencies, certificate renewals, integrations, storage needs, backups, and troubleshooting for engineering and business applications.
* Collaborate with software, engineering, and Dev Ops teams to support build infrastructure, source control access, and deployment-related system dependencies.
** Continuous Improvement and Technical Leadership
*** Identify opportunities to automate repetitive administration tasks using Power Shell, scripting, configuration management, or workflow automation.
* Lead or support infrastructure modernization projects, migrations, upgrades, hardening initiatives, and service improvements.
* Mentor junior administrators and service desk personnel by sharing knowledge, reviewing work, and promoting operational best practices.
* Evaluate new technologies, tools, and processes that improve reliability, security, supportability, and user experience.
* Participate in scheduled maintenance, after-hours support, and on-call escalation as needed.

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** Required Qualifications**--
- * 7+ years of hands-on systems administration, infrastructure operations, or related IT experience.
* 3+ years of experience operating in a senior, lead,…