1,242 Systems Administrator jobs in the United States

The System Administrator is responsible for installing, configuring, maintaining, and supporting an organization’s IT infrastructure. They ensure the stability, security, and efficiency of computer systems, networks, and servers, while providing technical support to users.

Key Responsibilities:

• Install, configure, and maintain servers, networks, and operating systems.
• Monitor system performance and troubleshoot issues to ensure minimal downtime.
• Manage user accounts, permissions, and access control.
• Perform regular system updates, patches, and backups.
• Implement and maintain cybersecurity measures to protect data and systems.
• Monitor network traffic, identify vulnerabilities, and resolve security breaches.
• Provide technical support and training to staff on IT-related issues.
• Maintain documentation of systems, configurations, and procedures.
• Collaborate with IT teams to plan and implement new technologies.
• Ensure compliance with IT policies, standards, and regulations.

Qualifications & Skills:

• Bachelor’s degree in Computer Science, Information Technology, or related field (or equivalent experience).
• Proven experience as a System Administrator, Network Administrator, or similar role.
• Strong knowledge of operating systems (Windows, Linux, macOS).
• Familiarity with virtualization, cloud services, and backup solutions.
• Understanding of networking (LAN/WAN, DNS, DHCP, VPN, firewalls).
• Problem-solving skills and ability to work under pressure.
• Excellent communication and teamwork abilities.
• Relevant certifications (CompTIA Server+, Microsoft, Cisco, or Red Hat) are an advantage.

Work Environment:

System Administrators typically work in offices, data centers, or remotely. The role may require being on call for emergencies, working with sensitive information, and managing multiple projects simultaneously.

ManTech seeks an experienced and passionate, career and customer-oriented System Administrator to join our team located in the San Antonio, TX area.

Responsibilities include, but are not limited to:

• Demonstrate experience creating and managing virtual environments (VMWare ESX, VCenter Administration) 
• Experience in administration of Linux
• Experience configuring and maintaining storage and file systems (NFS, EXT3/4, XFS) 
• Experience in developing and delivering briefings, technical presentations, and program documentation to senior program management 

Minimum Qualifications:

• Bachelor’s degree in computer science or a related discipline and 7 years related experience or associate’s degree in computer science or a related discipline and 11 years related experience
• Experience using Ansible
• Experience writing scripting languages (Bash, Shell, Python, Perl) 
• Proficiency in working with applicable network devices to include routers and switches, gateways and hubs 
• Experience with computer networking protocols including, but not limited to TCP, IP, UDP, HTTP, DHCP, and DNS   
• Experience working with a team to introduce and integrate new technologies into existing production environments 
• Experience with integrated processing environments such as a Storage Area Network  

Preferred Qualifications:

• Experience with DevOps tools such as Docker, Kubernetes, SALT, Puppet
• Experience with cross-domain solutions or NiFi desirable for some positions 
• Experience with computer operating systems

Clearance Requirement:

• Must have a current/active TS/SCI with Poly

Physical Requirements:

• Must be able to remain in a stationary position at least 50% of the time.
• Needs to occasionally move about inside the office to access file cabinets, office machinery, etc.
• Constantly operate a computer and other office productivity machinery, such as, the copy machine/fax machine/computer/printer.

ManTech seeks an experienced and passionate, career and customer-oriented System Administrator to join our team located in the San Antonio, TX area.

Responsibilities include, but are not limited to:

• Demonstrate experience creating and managing virtual environments (VMWare ESX, VCenter Administration) 
• Experience in administration of Linux
• Experience configuring and maintaining storage and file systems (NFS, EXT3/4, XFS) 
• Experience in developing and delivering briefings, technical presentations, and program documentation to senior program management 

Minimum Qualifications:

• Bachelor’s degree in computer science or a related discipline and 7 years related experience or associate’s degree in computer science or a related discipline and 11 years related experience
• Experience using Ansible
• Experience writing scripting languages (Bash, Shell, Python, Perl) 
• Proficiency in working with applicable network devices to include routers and switches, gateways and hubs 
• Experience with computer networking protocols including, but not limited to TCP, IP, UDP, HTTP, DHCP, and DNS   
• Experience working with a team to introduce and integrate new technologies into existing production environments 
• Experience with integrated processing environments such as a Storage Area Network  

Preferred Qualifications:

• Experience with DevOps tools such as Docker, Kubernetes, SALT, Puppet
• Experience with cross-domain solutions or NiFi desirable for some positions 
• Experience with computer operating systems

Clearance Requirement:

• Must have a current/active TS/SCI with Poly

Physical Requirements:

• Must be able to remain in a stationary position at least 50% of the time.
• Needs to occasionally move about inside the office to access file cabinets, office machinery, etc.
• Constantly operate a computer and other office productivity machinery, such as, the copy machine/fax machine/computer/printer.

**Description**
**Exciting Opportunity with Leidos: System Administrator - Davis Monthan AFB, AZ**
Leidos is seeking a highly skilled System Administrator to join our team at Davis Monthan Air Force Base, Arizona. This is a mission-critical role supporting national security operations, and candidates must hold a current TS/SCI security clearance to be considered.
**Your Impact**
As the System Administrator, you'll take charge of JWICS operations across all Wing and subordinate unit SCIFs on site. You'll lead site-wide JWICS C4I (Command, Control, Communications, Computers, and Intelligence **)** efforts, performing hands-on maintenance to install and sustain computers, servers, and all JWICS-related software and hardware.
Your responsibilities will include:
+ Account management, network storage, authentication servers, file servers, user privileges, group policy, software testing, restoration operations, contingency planning, and local backups.
+ Ensuring timely security patching and pushing JAVA, NOTAMS, and TCNO patches that cannot be deployed remotely by the AF JWICS Enterprise.
**Primary Responsibilities:**
+ Collaborate directly with users and coordinate daily with ESD and ESC AF to resolve network issues and maintain domain integrity.
+ Support the Cyber Security Operations Center with investigative administration for malware, spyware, Trojans, and unauthorized software.
+ Provide full-time operational support, with potential for after-hours and weekend on-call duty.
+ Operate independently with minimal oversight, while also working closely with team members to fulfill mission objectives.
+ Apply analytical and evaluative methods to assess information, plan actions, and solve complex security challenges.
+ Assist USAF and other government agencies in developing SSO documents, presentations, formal messages, background papers, and administrative materials.
+ Perform SCI security support functions and access JWICS systems within the SCIF.
**What Sets you Apart (Required):**
+ Active TS/SCI security clearance
+ Current Security+ certification
+ Bachelor's degree in IT, Information Assurance, or related field with 9+ years of relevant experience, or a Master's degree with 7+ years. Additional experience may be considered in lieu of a degree.
This is a unique opportunity to make a meaningful impact in a high-security environment while working with cutting-edge systems and a dedicated team. If you're ready to take your career to the next level, we'd love to hear from you.
EIO2024
At Leidos, we don't want someone who "fits the mold"-we want someone who melts it down and builds something better. This is a role for the restless, the over-caffeinated, the ones who ask, "what's next?" before the dust settles on "what's now."
If you're already scheming step 20 while everyone else is still debating step 2. good. You'll fit right in.
**Original Posting:**
October 20, 2025
For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above.
**Pay Range:**
Pay Range $72,150.00 - $130,425.00
The Leidos pay range for this job level is a general guideline onlyand not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.
#Featuredjob
REQNUMBER: R-
All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability or veteran status. Leidos will consider qualified applicants with criminal histories for employment in accordance with relevant Laws. Leidos is an equal opportunity employer/disability/vet.