Job ID# 10TEK0837-021126 – Posted 02/11/2026 – Remote, Downey, CA

We are seeking a highly experienced Senior Mainframe Systems Programmer to support and enhance legacy z/OS environments. This role is responsible for the planning, implementation, maintenance, and optimization of enterprise mainframe operating systems and associated infrastructure.

The ideal candidate will bring deep expertise in IBM z/OS systems programming, mainframe architecture, performance tuning, and security integration. This is a systems programming role (not a development position).

• Plan and execute system upgrades in accordance with County standards

• Monitor system health and implement required changes

• Analyze issues reported by development teams and provide technical recommendations

• Design and maintain systems architecture

• Coordinate post-upgrade application testing with stakeholders

• Ensure compatibility between operating systems and software products

• Perform hardware upgrades with minimal downtime

• Evaluate emerging software technologies

• Ensure timely patching of security-related products

• Analyze system requirements, risks, and cost considerations

• Evaluate, select, install, and validate system software environments

• Install and maintain compilers, assemblers, and utilities

• Integrate hardware and software components across enterprise environments

• Monitor, tune, and optimize system performance

• Evaluate new systems engineering technologies and assess their impact

• Ensure information security and assurance principles are integrated into system environments

• Extensive hands-on experience with IBM mainframe technologies, including:

  • z/OS

  • IMS (DB/DC)

  • DB2

  • ADABAS

  • SMP/E

  • JCL

  • CICS

  • ACF2

  • Assembler, COBOL, REXX

  • Control-M

  • VTAM

  • TCP/IP

  • NetView

  • Natural / SuperNatural

  • EntireX

  • CA Spool

  • IMS & DB2 BMC Tools

  • HMC / HOD / IODF

  • VTS

  Additional Required Technologies

  • HCD

  • z/OSMF

  • IBM z16 and z17 hardware

  • CA ACF2 V17

  • HOD V16.1

• Minimum 7 years of z/OS systems programming experience

• At least 4 years in a lead or senior-level role

• Extensive knowledge of mainframe hardware and system software environments

Bachelor’s degree in Information Technology, Engineering, or related field
(Additional qualifying experience may substitute for education on a year-for-year basis.)