Mainframe Implementation Manager

Whitehall Resources currently require an experienced Mainframe Implementation Manager to work with a key client.

**Please note this role falls INSIDE IR35**

Role purpose: Plan, coordinate, and execute the end-to-end implementation of a mainframe product migration into production, ensuring a controlled, compliant, and low-risk cutover. Own the integrated deployment/cutover plan, readiness, and go/no-go governance across technology, operations, business, and third parties.

Key responsibilities

• Create and maintain the integrated implementation (deployment/cutover) strategy and plan covering scope, approach (big bang/phased), timeline, dependencies, and critical path.
• Lead cutover planning: detailed runbooks, rehearsal plans, roles/responsibilities, communications, checkpoints, and contingency/rollback.
• Coordinate release and change management activities (CAB submissions, implementation approvals, change records, stakeholder signoffs).
• Drive environment and operational readiness: capacity, access, monitoring, scheduling/batch windows, support model, service transition.
• Manage data migration implementation activities with clear sequencing, validation steps, reconciliation, and operational controls.
• Orchestrate dress rehearsals / mock cutovers, capture lessons learned and harden runbooks.
• Lead implementation governance: readiness reviews, RAID management, decision logs, and executive reporting.
• Coordinate hyper care/post-go-live: incident triage, defect backlog prioritisation, stabilisation metrics, and handover to BAU.
• Ensure alignment with risk/compliance/audit requirements (evidence packs, approvals, segregation of duties where required).
• Manage third parties/vendors involved in deployment (e.g., infrastructure, platform, data, app support, schedulers).
• Implementation strategy and Integrated Cutover Plan
• Detailed cutover runbooks (minute-by-minute where needed)
• Rehearsal plans and rehearsal outcomes/actions log
• Change/CAB artefacts and approval pack
• Readiness criteria, go/no-go checklist, and decision log
• Hypercare plan, support model, and BAU handover pack
• Implementation closure report and lessons learned

Required experience

• Proven Implementation/Cutover/Deployment Management on mainframe or large-scale legacy migrations.
• Strong understanding of z/OS production operations constraints: batch cycles (JCL), scheduling (e.g., Control-M/CA-7), DB2/IMS considerations, CICS regions, interface dependencies, and resilience/DR practices.
• Experience running dress rehearsals, coordinating cross-team cutovers, and leading go/no-go forums.
• Working knowledge of ITIL-aligned change, release, and incident management in regulated environments.