Administer and support enterprise server, cloud, network, identity, and Microsoft 365 infrastructure. Deploy and maintain Windows, AWS, Azure, and collaboration platforms; manage patches, backups, disaster recovery, monitoring, capacity, security controls, and automation. Provide escalation-level support within SLAs, document environments, follow change-management procedures, participate in on-call rotations, and mentor junior staff. The role is remote or hybrid in the US with occasional customer travel.