Senior Security Administrator

About the RoleWe’re looking for a hands-on Senior Systems & Security Administrator to own its infrastructure, security operations, and automation. You'll work directly with leadership and technical staff to strengthen the firm's security posture, keep systems resilient, and support its compliance goals.What You'll DoRun the firm's hybrid environment (cloud and on premises) across several offices, covering endpoints, network gear, and security tooling.Own identity and access in Entra ID: user lifecycle, MFA, conditional access, SSO, and privileged accounts.Administer Microsoft 365 (Exchange Online, SharePoint, OneDrive, Teams, Purview) and manage devices through Intune and Autopatch.Maintain firewalls, VLANs, wireless, VPN, and web filtering.Monitor EDR and DLP tools (SentinelOne, Defender), triage alerts, and work alongside an outsourced SOC.Lead incident response from containment through recovery, including root cause reviews.Drive vulnerability management, patching, and pen test remediation.Build and enforce change management, hardening standards, and update procedures.Manage backups and DR, including restore testing and business continuity exercises.Track hardware, licenses, and secure media disposal; act as custodian for encryption keys.Support audits, client security questionnaires, and ISO 27001 certification work.Automate routine tasks with PowerShell, Microsoft Graph, and native platform workflows, and document everything so others can support it.Secure the firm's AI platforms and help guide responsible adoption of new AI tools.What You Bring5+ years in systems administration, including 3+ at a senior level in production environments.Experience working within a formal compliance framework such as ISO 27001, SOC 2, NIST CSF, or HIPAA.Deep knowledge of the Microsoft cloud stack, enterprise networking, and endpoint security.Advanced PowerShell and Graph scripting skills.Disciplined documentation habits: runbooks, change logs, baselines, and audit evidence.Certifications such as CISSP, CISM, GIAC, SC-100, SC-300, or MD-102 are a plus.