ERNESTO J. DÍAZ

Lead Systems Administrator  |  Leadership · Cloud · Identity · Security · Automation

Professional Summary

Lead Systems Administrator with 15+ years of experience across fintech, healthcare, MSP, and higher education. Specialized in AWS/Azure, virtualization, identity, security hardening, and automation. Known for leading cross-team initiatives, improving system reliability, reducing risk, and using PowerShell + AI-assisted tooling to accelerate IT workflows and reduce operational overhead.

Professional Experience

Lead Systems Administrator
Feb 2022 – Present
Shift4 Payments · Fintech
  • Manage a 6-person, multi-timezone team (West Coast, East Coast, Malta), aligning prioritization, escalations, and delivery across infrastructure, identity, and security initiatives.
  • Develop System Administrators and enable Help Desk through training and runbooks, improving troubleshooting consistency and reducing escalations.
  • Act as primary technical interface for Security/Network/DevOps leadership on risk, remediation priorities, and delivery timelines.
  • Serve as incident commander for high-severity events, driving triage, stakeholder communications, and root-cause analysis to reduce repeat incidents.
  • Plan and manage maintenance windows for critical systems, coordinating change execution, stakeholder comms, and rollback readiness.
  • Own operational readiness across enterprise platforms by ensuring server/OS and internally managed VMware environments remain patched, supported, and compliant.
  • Manage AWS infrastructure, performance monitoring, and high-availability configurations for critical systems.
  • Led enterprise server migration (100+ systems), increasing uptime by ~20%.
  • Implement and maintain Okta SSO integrations for critical platforms (Slack, GitLab, Salesforce, Monday.com).
  • Oversee user provisioning and license administration; collaborate with Procurement and leadership on renewals and contracts.
  • Oversee Ivanti patch management, antivirus automation, and endpoint hardening.
  • Partner with Security to test, deploy, and tune security tooling across enterprise systems, including CrowdStrike, Wiz, and Qualys, driving faster detection and remediation of vulnerabilities and endpoint risks.
  • Migrate 20+ domains to Cloudflare for improved DNS security and threat mitigation.
  • Build Confluence SOPs/runbooks to keep operations documented and repeatable (maintenance workflows, escalation paths, and standard procedures).
  • Develop custom PowerShell automation to reduce repetitive work, improve SLAs, and accelerate troubleshooting and response.
  • Participate in forensic analysis and security investigations alongside Security and Network teams.
  • Collaborate with Network Engineering to optimize firewall rules and reduce exposure.
  • Actively incorporate AI-assisted tooling to accelerate troubleshooting and script development.
AWS Systems Administrator
May 2021 – Feb 2022
Ironistic · Digital Agency / Hosting
  • Managed full AWS architecture including EC2, ELB, S3, IAM, and Route 53.
  • Maintained uptime and security of 500+ hosted websites across mixed Linux/Windows environments.
  • Administered 45+ servers, performed lifecycle upgrades, and handled Plesk hosting operations.
  • Configured and managed Cloudflare DNS and security configurations.
  • Supported clients through PenTest results, remediation, and infrastructure troubleshooting.
Senior / Lead Systems Administrator
2019 – 2021
Stetson University · Higher Education
  • Administered 60+ Windows servers across VMware ESXi and Hyper-V environments.
  • Built the first VMware cluster for the College of Law and migrated 30+ servers from Hyper-V to ESXi.
  • Led Tenable-based vulnerability remediation and patching programs.
  • Led a university-wide Microsoft MFA rollout and a SharePoint → Teams migration initiative.
  • Managed Druva-based backups and ongoing server maintenance for critical services.
Chief Information Officer
2017 – 2019
Millennial Networks · MSP
  • Provided full-stack MSP support to 50+ clients across servers, networks, and EMR platforms.
  • Designed and deployed VMware environments, Azure, Office 365, VoIP, and hosting solutions.
  • Trained and mentored a team of 5 junior admins while scaling MRR to ~$25K.
  • Reduced AWS spend by ~5% through usage analysis and right-sizing.
Systems Administrator
2014 – 2017
Eastern Consulting Group · Healthcare
  • Led migration to Windows Server 2012 R2 across 9 regions.
  • Delivered EMR training to 100+ medical staff and supported multi-office infrastructure.
  • Designed WAN/LAN using IPSec VPN and created disaster recovery documentation.
  • Managed VMware vSphere and core server infrastructure for medical practices.
Systems Administrator
2009 – 2014
Droguería Betances · Distribution / Healthcare
  • Maintained AS/400, servers, and networking for 24/7 operations.
  • Designed an iPad ordering system that generated ~$20M in its first year.
  • Built DR plans and Windows Failover Clusters for critical services.
  • Managed SFTP integrations for secure medical data workflows.
  • Led a company-wide Windows 7 migration project.

Core Competencies

Leadership & Operations
Team Leadership (Distributed) Incident Command / RCA Maintenance Windows Runbooks / SOPs Vendor & License Management
Cloud & Infrastructure
AWS (EC2, S3, Route 53, IAM, VPC) Azure VMware ESXi Hyper-V High Availability Monitoring
Identity & Security
Okta SSO Active Directory Duo MFA Cloudflare Ivanti EPM CrowdStrike Wiz Qualys Security Hardening SIEM (Splunk)
Automation & AI
PowerShell Automation Workflow Optimization AI-assisted scripting Predictive monitoring concepts
Networking & OS
FortiGate Firewalls IPSec VPN DNS · VLANs Windows Server Linux (CentOS/Ubuntu) macOS
Web & Tooling
Apache / Nginx WordPress Plesk / cPanel Icinga CloudWatch Jira · Confluence LanSweeper Ninite

Key Achievements

  • Promoted into Lead Systems Administrator roles (Stetson University, Shift4 Payments).
  • Scaled MSP operations at Millennial Networks to ~$25K MRR while leading a technical team.
  • Designed an iPad ordering system generating ~$20M in its first year of operation.
  • Migrated a datacenter to a co-location facility connecting 9 offices via secure networking.
  • Delivered large-scale MFA deployments and cloud migration projects across industries.

Languages

English – Fluent Spanish – Fluent