Senior Systems Administrator – M365 & Infrastructure

Linuxassociation; Markham; On-site; CAD 90,000 - 110,000; Full time

Job summary

Perseus Group, a part of Constellation Software, seeks a Senior Systems Administrator to manage M365 and infrastructure in Markham. You will oversee Entra ID, SSO, MFA, and licensing, while coordinating with IT leadership and vendors to ensure secure, scalable services.

The role emphasizes identity management, endpoint security, and collaboration platforms across the organization, with a focus on governance and reliability.

Qualifications

• 7+ years of IT infrastructure and systems administration experience.
• 5+ years administering Microsoft 365 environments.
• "Experience implementing and supporting SSO and Conditional Access."
• "Experience with Exchange Online, SharePoint Online, and Teams."
• "Experience administering Microsoft Intune and Windows Autopilot."
• "Strong understanding of Microsoft licensing and tenant governance."
• "Experience supporting cybersecurity and compliance initiatives."
• "Strong troubleshooting, analytical, and problem-solving skills."

Responsibilities

• Administer and maintain Microsoft Entra ID and user provisioning.
• Configure and manage SSO integrations and Conditional Access policies.
• Oversee Microsoft 365 services including Exchange Online, Teams, SharePoint Online, OneDrive, Power Platform, Power BI.
• Manage retention, compliance policies, mail flow, SPF/DKIM/DMARC and security controls.
• Administer Microsoft Intune and Windows Autopilot deployments.
• Support endpoint management, device compliance, patching, and remote workforce tech.
• Administer Teams Phone and collaboration services.
• Contribute to disaster recovery and security governance initiatives.

Skills

Entra ID

SSO

MFA

Microsoft 365

Intune

Windows Autopilot

Security governance

IT infrastructure

Identity governance

Troubleshooting

Tools

Exchange Online

SharePoint Online

Teams

Power Platform

Power BI

Intune

Job description

# Senior Systems Administrator – M365 & InfrastructurePerseus Group, Constellation Software · Markham, Ontario, CABack to resultsSenior Systems Administrator – M365 & InfrastructurePerseus Group, Constellation SoftwareMarkham, Ontario, CA Posted November 9, 2026 Via LinkedIn### Full Job DescriptionPosition SummaryConstellation HomeBuilder Systems is seeking a Senior Systems Administrator / M365 & Infrastructure Administrator to join our Information Technology team in Markham, Ontario.This role will be responsible for the administration, security, governance, and strategic operation of our Microsoft 365 environment, Microsoft Entra ID platform, endpoint management systems, and collaboration technologies. The position will own technology services and responsibilities transitioning from shared corporate IT services as part of our integration with Jonas.The successful candidate will serve as a senior technical resource responsible for identity and access management, Microsoft 365 administration, endpoint management, collaboration platforms, security governance, and infrastructure support. This individual will work closely with leadership, business stakeholders, and external vendors to ensure secure, reliable, and scalable technology services across the organization.Primary ResponsibilitiesIdentity & Access Management• Administer and maintain Microsoft Entra ID• Manage user provisioning, deprovisioning, and lifecycle management• Configure and maintain Single Sign-On (SSO) integrations• Design and administer Conditional Access policies• Manage Multi-Factor Authentication (MFA) technologies• Administer external collaboration and B2B access• Conduct identity governance reviews and access certifications• Manage Microsoft licensing and group-based assignments• Maintain role-based access controls and security standardsMicrosoft 365 Administration• Administer Microsoft 365 services including:• Exchange Online• Teams• SharePoint Online• OneDrive• Power Platform• Power BI• Manage retention and compliance policies• Configure and maintain mail flow and transport rules• Administer SPF, DKIM, and DMARC configurations• Implement and maintain Microsoft security controls• Support tenant governance and security best practices• Monitor service health and platform performance• Evaluate and implement new Microsoft 365 capabilitiesEndpoint Management• Administer Microsoft Intune• Manage Windows Autopilot deployments• Develop and maintain device compliance policies• Manage application deployment and lifecycle management• Oversee workstation configuration standards• Manage endpoint patching and security updates• Support remote workforce technologiesVoice & Collaboration• Administer Microsoft Teams Phone• Support TouchPoint and related communication systems• Troubleshoot voice and collaboration issues• Coordinate with telecom and technology vendors• Manage call routing, auto attendants, and user provisioning• Ensure reliable collaboration services across the organizationInfrastructure & Security• Support core Windows infrastructure services• Participate in infrastructure modernization initiatives• Assist with cloud and hybrid infrastructure administration• Maintain security baselines and operational standards• Participate in security investigations and remediation efforts• Create and maintain system documentation, procedures, and standards• Participate in disaster recovery and business continuity planningQualificationsRequired• 7+ years of IT infrastructure and systems administration experience• 5+ years administering Microsoft 365 environments• Strong experience with Microsoft Entra ID• Experience implementing and supporting SSO and Conditional Access• Experience with Exchange Online, SharePoint Online, and Teams• Experience administering Microsoft Intune and Windows Autopilot• Strong understanding of Microsoft licensing and tenant governance• Experience supporting cybersecurity and compliance initiatives• Strong troubleshooting, analytical, and problem-solving skills• Excellent written and verbal communication skillsPreferred• Microsoft certifications such as:• Microsoft Certified: Identity and Access Administrator• Microsoft Certified: Enterprise Administrator Expert• Microsoft Certified: Security Administrator Associate• Microsoft Certified: Endpoint Administrator Associate• Experience with Teams Phone• Experience with Power BI administration• Experience with Palo Alto Networks security solutions• Experience supporting mergers, acquisitions, or tenant migrations• Experience working in SaaS or software organizations• Knowledge of Azure services and cloud administrationSuccess MeasuresThe successful candidate will:• Maintain a secure and compliant Microsoft 365 environment• Ensure timely onboarding and offboarding processes• Maintain high endpoint compliance and patching standards• Deliver reliable collaboration and communication services• Improve operational efficiency through automation and standardization• Maintain accurate documentation and governance processes• Successfully assume and operate services transitioning from shared corporate IT functionsSalary Range (Ontario & BC Only):The estimated base salary range for this role is CAD$90,000.00 - CAD$110,000.00 per year. We include salary ranges in job postings only where required by applicable pay transparency laws, based on the jurisdictions in which the role may be performed. The posted range is a good faith estimate and reflects factors that are subject to change. Final offer amounts may vary based on job-related factors, including work location, candidate experience and expertise, and other relevant considerations.We recognize the value and importance of diversity and inclusion in our communities and in the workplace. We celebrate diversity and one of our goals as an employer is to create an inclusive work environment for all employees. We are an equal opportunity employer and do not discriminate against any employee or applicant because of race, religion, sex, sexual orientation including gender identity or expression, pregnancy, national origin, age, marital status, veteran status, disability status, or any other category or characteristic protected by law.Applicants with disabilities who would like to require a reasonable accommodation related to any part of the application process may contact us at Perseus\\[e-mail].#HB HO#### Apply for this JobThis will take you to the original posting on the employer's site. Apply NowVia LinkedIn#### Job SummaryCompanyPerseus Group, Constellation SoftwareLocationMarkham, Ontario, CATypeFull-timePostedNovember 9, 2026SourceLinkedIn