Payroll implementation support specialist (contract)

Contract Duration: 3–5 months

About GreenLight.ai
GreenLight is an enterprise workforce solutions company providing EOR, AOR, FMS, worker classification, payroll coordination, compliance, and workforce management technology for complex contingent workforce programs. We are replacing our current payroll provider and implementing a new payroll solution across a complex U.S. and international payroll environment. The new provider will integrate with GreenLight’s proprietary platform, so this role will sit at the intersection of payroll operations, implementation execution, data validation, testing, and system integration coordination.

About the Role

We are seeking a Payroll Implementation Support Specialist to help drive the implementation of GreenLight’s new payroll provider. This person will partner with Payroll, HR, Finance, Engineering/Product, and the selected payroll provider to support implementation planning, data migration, configuration validation, integration coordination, testing, cutover, go-live readiness, and post-launch stabilization.

The ideal candidate has hands-on experience with complex payroll implementations, including multi-state U.S. payroll, high-volume hourly workforces, and ideally multi-country payroll exposure. This person does not need to be an engineer, but should be comfortable coordinating technical workstreams and working with internal and vendor teams on system integrations, data flows, testing, and issue resolution.

Key Responsibilities

• Support the payroll implementation project plan, including workstream tracking, milestone management, dependency tracking, issue/risk logs, and status updates.
• Coordinate across Payroll, HR, Finance, Engineering/Product, the selected payroll provider, and any implementation partners to keep workstreams moving.
• Support requirements validation, payroll process documentation, system readiness, and operational handoff planning.
• Assist with payroll data migration, mapping, cleansing, validation, and reconciliation.
• Support validation of payroll configurations, including earnings and deduction codes, tax setup, payroll calendars, worker setup, and payroll processing rules.
• Coordinate with Engineering/Product and vendor technical teams on the integration between GreenLight’s platform and the payroll provider.
• Support validation of key data flows between GreenLight’s platform and the payroll provider, including worker records, payroll inputs, payroll results, tax/deduction data, payment status, and reporting outputs.
• Support user acceptance testing, integration testing, and parallel payroll testing.
• Investigate discrepancies during testing, document root causes, and track issues through resolution.
• Support cutover planning, go-live readiness, payroll calendar alignment, and post-implementation stabilization.
• Develop process documentation, testing materials, cutover checklists, job aids, and knowledge transfer materials for ongoing payroll operations.
• Provide hands-on support during hypercare for the first payroll cycles after go-live.

Required Qualifications

• 5–8+ years of experience in payroll operations, payroll systems, payroll implementation, or payroll implementation support.
• Hands-on involvement in at least one complex payroll system or payroll provider implementation.
• Strong understanding of complex payroll environments, including U.S. multi-state payroll.
• Experience with high-volume hourly payroll, variable pay, frequent worker changes, payroll cutoffs, exceptions, and reconciliation.
• Experience supporting data validation, payroll reconciliation, parallel payroll testing, and issue resolution.
• Ability to coordinate cross-functional workstreams across payroll, HR, finance, engineering/product, vendors, and implementation partners.
• Comfortable working with technical teams on integrations, data flows, field mapping, testing, and issue tracking.
• Strong Excel skills and ability to analyze large datasets and identify discrepancies.
• Strong communication, documentation, and project coordination skills.
• Availability for a 3–5 month contract.

Preferred Qualifications

• Experience supporting payroll implementations across multiple countries or multiple payroll providers.
• Experience with U.S. and international payroll implementations, ideally including Canada, the UK, and EU countries.
• Experience supporting payroll integrations with HCM/HRIS, time and attendance, benefits, finance, general ledger, or other operational systems.
• Experience working with API-based integrations, vendor technical teams, sandbox testing, integration test scripts, and system-to-system reconciliation.
• Experience with complex hourly, contingent workforce, staffing, EOR, or payrolling environments.
• Experience working with third-party implementation partners in a complex enterprise or multi-entity environment.
• CPP, FPC, PMP, or similar certification is helpful but not required.

Engagement Details

This is a temporary contract role expected to last approximately 3–5 months. The role will support GreenLight through implementation, testing, cutover, go-live, and initial stabilization of the new payroll provider. The successful candidate will be practical, detail-oriented, hands-on, and comfortable operating between payroll operations, finance, HR, engineering, and vendor teams.