Senior Systems Administrator

Are you a hands-on Systems Administrator who enjoys solving complex infrastructure problems and working across a variety of client environments?

We're looking for a Senior Systems Administrator to join a growing managed IT services provider supporting clients across the Greater Toronto Area. This is a hands-on role with a strong focus on virtualization, Microsoft 365, Azure, and networking
.

The ideal candidate has strong infrastructure experience, is comfortable working directly with clients, and can take ownership of technical issues from troubleshooting through to resolution.

• Fully Onsite - 5 days a week in-office or visiting client sites; on-call and after hours support when required
• Location: Toronto, ON
• Work Type: This is a newly created position

• Manage and troubleshoot virtualized infrastructure
  , including Nutanix HCI environments
• Administer and support Microsoft 365 environments, including Exchange Online, SharePoint, Teams, One Drive, and user/license management
• Support Azure and Entra environments, including hybrid identity and cloud infrastructure
• Configure, maintain, and troubleshoot network infrastructure
  , including LAN/WAN, VLANs, firewalls, VPNs, and Wi‑Fi
• Serve as a senior escalation point for complex technical issues and Level 1/2 tickets
• Support server, endpoint, operating system, and infrastructure‑related issues across client environments
• Lead and support infrastructure projects, including migrations, upgrades, and implementations
• Monitor system health and proactively identify and resolve potential issues
• Maintain accurate technical documentation, network diagrams, and infrastructure standards
• Work directly with clients and vendors to resolve technical issues and deliver solutions
• Provide technical guidance and mentorship to junior technicians
• Apply security best practices across client systems and infrastructure

• 5+ years of experience in Systems Administration, Infrastructure Engineering, or a similar role
• Experience working within an MSP, managed services, or multi‑client environment
• Hands‑on experience administering Nutanix HCI
  , including cluster management and AHV/VM administration
• Strong experience administering Microsoft 365
  , including Exchange Online, SharePoint, Teams, and One Drive
• Experience with Azure and Microsoft Entra , including hybrid environments
• Solid understanding of networking
  , including LAN/WAN, VLANs, firewalls, VPNs, and routing
• Experience with Windows Server and on‑premises Active Directory
• Experience with RMM and PSA platforms;
  HaloPSA and Ninja One are an asset
• Strong troubleshooting and problem‑solving skills
• Experience mentoring, coaching, or providing technical direction to junior technicians
• Strong client‑facing communication skills and the ability to work with both technical and non‑technical stakeholders
• Strong organizational skills and the ability to manage multiple client environments and competing priorities

• Cybersecurity experience from a systems/infrastructure administration perspective
• Experience with Sentinel One, Microsoft Defender, or other EDR/MDR platforms
• Forti Gate or other firewall experience
• Microsoft 365 security experience, including Conditional Access, MFA, Intune, and DLP
• Experience with infrastructure migrations to Azure/Microsoft 365
• ITIL Foundation or working knowledge of ITIL practices
• Experience supporting law firms or professional services organizations
• Experience with operational technology (OT), building automation, or commercial property environments
• Nutanix or Microsoft certifications

• Technical Variety: Work across virtualization, cloud, Microsoft 365, networking, and infrastructure
• Client Exposure: Work directly with a diverse client base and become a trusted technical resource
• Hands‑On Environment: Take ownership of real infrastructure challenges and projects
• Technical Growth: Continue developing your expertise across modern infrastructure and cloud technologies
• Leadership Opportunity: Mentor junior technicians and play a key role in supporting the broader technical team
• Performance Bonus Eligibility
• Paid Time Off & Extended Health Benefits (Medical/Dental/Vision)
• Professional development, training, and certification opportunities

We're committed to diversity and inclusion. Need accommodation during the hiring process? Let us know, we're here to support you!

AI Use Disclosure:

STACK IT uses AI-enhanced tools to support initial candidate screening and interview note analysis. All assessments and hiring decisions remain human‑led.