MSP Security Engineer — Onsite/Hybrid Ops

Fusethree; California; On-site; USD 110,000 - 160,000; Full time

Job summary

FUSE3 is seeking a Security Engineer to join our Information Security team in Fair Oaks, CA. This mid-level role bridges day-to-day operational security work with advanced technical execution, owning recurring tasks and supporting the management of our security toolset across client environments.

You will diagnose and resolve complex security issues, manage tools like Defender and MFA configurations, and contribute to incident response activities while documenting procedures for the knowledge

Qualifications

• 3+ years in IT security or a closely related technical role.
• Strong working knowledge of Microsoft 365 and Entra ID administration and security.
• Hands-on experience with Active Directory administration and security (Group Policy, identity management, hybrid AD environments).
• Hands-on experience with core security tooling: endpoint detection/response, email security (phishing triage), MFA, and vulnerability management.
• Experience with Windows endpoint hardening and security baselines (e.g., CIS Benchmarks, Microsoft security baselines).
• Demonstrated ability to independently troubleshoot and resolve complex technical problems with minimal supervision.
• Solid understanding of networking fundamentals, identity/access management, and common attack vectors.
• Clear written and verbal communication skills, including the ability to document technical work and communicate effectively with both colleagues and clients.
• Ability to manage competing priorities across multiple clients or environments.

Responsibilities

• Handle escalated security tickets and incidents that require deeper technical investigation than front-line triage, working within our ticketing/PSA platform to track and resolve issues.
• Independently diagnose, troubleshoot, and resolve complex security and infrastructure issues across client environments.
• Help manage the full security toolset (endpoint protection, email security, MFA, vulnerability management, and related platforms), and own the day-to-day administration and tuning of assigned tools.
• Participate in the full vulnerability lifecycle from identification through patching and remediation alongside recurring tasks such as alert triage, configuration audits, and reporting.
• Support security project execution, including deployments, migrations, and remediation work.
• Assist with incident response activities under the direction of senior team members.
• Create and maintain clear, reusable documentation of procedures, configurations, and resolutions in the team's knowledge base.
• Collaborate with senior engineers to translate security plans into executed work.

Skills

Microsoft 365/Entra ID

Active Directory

Endpoint security tools

Phishing triage

Vulnerability management

Networking fundamentals

Documentation

Communication

Tools

PowerShell

Microsoft Defender

Huntress

Duo

SIEM platforms

Job description

FUSE3 is seeking a Security Engineer to join our Information Security team in Fair Oaks, CA. This mid-level role bridges day-to-day operational security work with advanced technical execution, owning recurring tasks and supporting the management of our security toolset across client environments.

You will diagnose and resolve complex security issues, manage tools like Defender and MFA configurations, and contribute to incident response activities while documenting procedures for the knowledge