IBM Mainframe Systems Engineer (Chicago/Remote US)

Our customer is a large United States insurance company that is backed by more than 100 years of experience and provides insurance products and services for businesses and professionals in the United States., Canada and Europe. Headquartered in Chicago, IL, they have more than 20 US locations.

We are seeking a contract IBM Mainframe Full‑Stack Systems Engineer experienced with end‑to‑end engineering and modernization of large‑scale enterprise IBM Z environments. This role requires deep, hands‑on expertise across multiple z/OS versions, core subsystems, security platforms, storage, networking, virtualization, and performance management in highly regulated, mission‑critical environments.

This role is engineering‑first, focused on architecture, deep technical analysis, system tuning, and modernization readiness. The engineer will play a critical role in proofing the mainframe platform, ensuring technical compatibility, stability, and performance as the stack evolves.

This role is hybrid (preferred) in Chicago, but can be 100% remote for the right candidate.

Responsibilities:

• Engineer and support modernization and upgrade activities across multiple concurrent z/OS environments and versions.
• Manage version interoperability, incremental upgrade paths, dependency validation, pre-upgrade assessments, post-upgrade stabilization, and system tuning.
• Provide deep engineering expertise across IBM Z core subsystems, including DB2 for z/OS, CICS TS, IMS DB/DC, and IBM MQ for z/OS.
• Support subsystem configuration, workload tuning, modernization readiness, and performance optimization across the mainframe stack.
• Analyze MQ subsystem behavior during z/OS and middleware upgrades, including dependency analysis with CICS, DB2, IMS, and distributed systems.
• Support TLS-enabled architectures and modernization initiatives across middleware and networking environments.
• Support enterprise schedulers such as CA-7, Control-M, and related ISV tooling.
• Assess compiler and language version dependencies and identify recompilation requirements during upgrade initiatives.
• Support integrations involving CDC tools, ETL platforms, DB2 Gateway, and terminal emulators.
• Maintain a holistic understanding of cross-subsystem dependencies during modernization and upgrade efforts.
• Provide engineering guidance for mainframe storage, networking, virtualization, and infrastructure modernization.
• Support z/VM and virtualized environment design and optimization.
• Identify infrastructure constraints impacting modernization, scalability, and performance improvements.
• Engineer and review RACF and ACF2 security controls, auditing, logging, and compliance enforcement.
• Partner with risk, audit, and application teams to support security policy alignment and regulatory compliance.
• Support mainframe security best practices, including encryption of data in transit.
• Leverage SMF, RMF, and operational metrics to analyze performance, identify bottlenecks, and support capacity planning.
• Recommend tuning opportunities to optimize throughput, response time, scalability, and operational efficiency.
• Identify automation opportunities using REXX, CLIST, JCL, TSO/ISPF, and self-healing operational processes.
• Collaborate cross-functionally with application teams, middleware teams, security organizations, vendors, and infrastructure stakeholders.

Skills and Qualifications:

• Bachelor’s degree in Computer Science, Engineering, or equivalent professional experience.
• 8–12+ years of hands-on IBM Mainframe experience within large enterprise environments.
• Strong expertise with multiple z/OS versions and upgrade processes.
• Strong experience with z/VM environments.
• Expertise with RACF and ACF2 security platforms.
• Deep experience with DB2 for z/OS, CICS, IMS, and IBM MQ.
• Strong understanding of TLS encryption within mainframe environments.
• Strong experience with mainframe storage, networking, SNA, VTAM, and TCP/IP.
• Experience with SMF, RMF, performance monitoring, and capacity management.
• Advanced proficiency with JCL, REXX/CLIST, and TSO/ISPF.
• Strong troubleshooting, root cause analysis, and documentation skills.
• Experience supporting modernization and platform engineering initiatives.
• Experience with enterprise schedulers and ISV tooling.
• Understanding of CDC tools, ETL platforms, DB2 Gateway, and terminal emulators.
• Strong cross-functional collaboration and communication skills.
• Experience working within regulated industries such as financial services, insurance, or government environments is preferred.

We offer a competitive salary range for this position. Most candidates who join our team are hired at the median of this range, ensuring fair and equitable compensation based on experience and qualifications.

Contractor benefits are available through our 3rd Party Employer of Record (Available upon completion of waiting period for eligible engagements)

Benefits include: Medical, Dental, Vision, 401k.

An Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability.