L3 Senior Escalations MSP Engineer

SUMMARY We are seeking a highly experienced Senior L3 MSP Engineer to join our US-based Managed Services team. This role is responsible for handling complex technical escalations from L1/L2 engineers, resolving critical infrastructure and networking issues, and providing advanced technical expertise across multiple client environments. The Senior L3 MSP Engineer will serve as a senior escalation point for the Service Desk and MSP Engineering teams, taking ownership of high-impact incidents that require advanced troubleshooting, root-cause analysis, infrastructure expertise, and coordination with vendors and client technical teams. This position requires strong experience in a Managed Service Provider (MSP) environment, excellent troubleshooting skills, and the ability to work across networking, Microsoft cloud technologies, servers, security, and client infrastructure. JOB RESPONSIBILITIES L3 Technical Escalations Act as the primary L3 escalation point for complex technical issues escalated by L1 and L2 engineers. Troubleshoot and resolve high-severity incidents involving networking, servers, Microsoft 365, cloud services, security, and client infrastructure. Take ownership of escalated tickets through resolution, ensuring proper communication, documentation, and follow-through. Perform advanced troubleshooting when issues cannot be resolved through standard L1/L2 procedures. Provide technical guidance and mentoring to L1/L2 MSP Engineers. Participate in major incident response and provide technical leadership during critical outages. Network & Infrastructure Troubleshoot complex LAN/WAN, routing, switching, VPN, firewall, DNS, DHCP, and connectivity issues. Diagnose issues involving TCP/IP, VLANs, NAT, routing, wireless, and site-to-site/remote-access VPNs. Support and troubleshoot enterprise firewalls such as SonicWall, Sophos, Fortinet, or similar technologies. Troubleshoot network performance, packet loss, latency, connectivity, and security-related incidents. Support Windows Server infrastructure, Active Directory, Group Policy, DNS, DHCP, file services, and virtualization environments. Assist with infrastructure migrations, upgrades, implementations, and complex remediation projects. Microsoft 365 & Cloud Provide advanced support for Microsoft 365, Exchange Online, Microsoft Entra ID, Intune, Teams, SharePoint, and OneDrive. Troubleshoot authentication, MFA, Conditional Access, identity synchronization, mail flow, permissions, and account-related issues. Investigate complex Microsoft 365 service and integration issues. Support Azure/Azure-related infrastructure and cloud connectivity where required. Security & Endpoint Troubleshoot advanced endpoints, antivirus/EDR, email security, and access-control issues. Support security platforms such as Sophos, Microsoft Defender, SonicWall, or similar technologies. Investigate security alerts and coordinate remediation with internal security teams and vendors. Assist with vulnerability remediation, patching, endpoint hardening, and security-related projects. MSP Operations Manage escalated tickets within defined SLA and priority requirements. Review recurring incidents and identify opportunities for permanent resolution. Perform root-cause analysis (RCA) and document findings for recurring or major incidents. Create and maintain technical documentation, knowledge articles, and troubleshooting procedures. Work closely with Account Managers, Service Desk teams, Project Engineers, and client IT teams. Communicate technical issues and resolutions clearly to both technical and non-technical stakeholders. Coordinate with third-party vendors and software/hardware providers when escalation is required. Participate in an on-call or after-hours escalation rotation when required. QUALIFICATIONS 7+ years of progressive IT infrastructure, systems, network, or MSP experience. 3+ years working at an L3/Senior Engineer level. Strong experience working in a US-based MSP or Managed Services environment. Proven experience handling L3 technical escalations from L1/L2 support teams. Strong troubleshooting skills across networking, servers, Microsoft 365, security, and infrastructure. Experience supporting multiple clients and different technical environments. Strong understanding of ITIL principles, incident management, problem management, and change management. Ability to perform root-cause analysis and develop permanent technical solutions. Excellent written and verbal communication skills. Strong documentation and knowledge-transfer skills. Ability to work independently while collaborating with engineers, vendors, and client stakeholders. JOB REQUIREMENTS Should be willing to accept a long-term work-from-home arrangement. Should be amenable to a permanent night shift schedule.