Corporate Controller in Milwaukee, Wisconsin at S3 AeroDefense LLC

Purpose of the Role:

The Corporate Controller is a newly created, hands-on leadership role that owns the day-to-day transactional accounting operations of S3 AeroDefense and its subsidiaries. As the company scales — organically and through acquisition — the Controller is responsible for running an accurate, timely, well-controlled, and increasingly automated transactional accounting engine, and for leading the accounting integration of acquired businesses.

This role is deliberately structured to complement a self-contained FP&A function. The Director of Finance and the FP&A team own the monthly close, financial and management reporting, technical accounting (including revenue recognition), budgeting, and forecasting. The Controller owns the transactional foundation those outputs are built on — accounts payable, accounts receivable and collections, payroll accounting, treasury and cash operations, inventory and cost-accounting transactions, the day-to-day integrity of the general ledger, and the internal control environment. Evaluating customers’ credit standing and managing limits and risk mitigation frameworks (such as credit insurance, D&B review, etc.). Success means transactional books that are clean, current, and audit-ready — freeing finance leadership to focus on strategy, reporting, and M&A.

Reports to: Chief Financial Officer

Location: Milwaukee, WI (in office with hybrid flexibility on certain days as needed)

Key Responsibilities

Transactional Accounting Operations

• Own end-to-end transactional accounting: accounts payable and disbursements; accounts receivable, billing, and collections; payroll accounting; cash and treasury operations; fixed assets; inventory and cost-accounting transactions; and intercompany transactional processing.
• Deliver clean sub-ledgers on schedule so the FP&A team can complete the monthly close and reporting without rework.
• Own account reconciliations across cash, AR, AP, inventory, accruals, and intercompany — resolving variances promptly and maintaining a documented, complete reconciliation cycle.
• Optimize working capital through disciplined management of payables, receivables and DSO, and cash application.

Internal Controls & Compliance

• Design, document, and operate a scalable control framework over transactional processes that is audit-ready today and can withstand increasing scrutiny (including SOX-style controls) as the company grows.
• Serve as a primary audit contact for transactional and balance-sheet areas, supporting a timely, clean external audit.

M&A Integration

• Lead the accounting integration of acquired entities: onboarding AP/AR/payroll/GL processes, mapping charts of accounts and systems, standardizing transactional policies, and establishing intercompany and consolidation mechanics.
• Support financial due diligence and own the transactional-accounting workstream for Day 1 readiness and post-close integration.
• Build a repeatable accounting-integration playbook that scales across multiple acquisitions and, where needed, multiple ERPs.

Systems, Process & Automation

• Own and continuously improve transactional processes in the Pentagon 2000SQL ERP; drive automation of high-volume, manual workflows (e.g., payment disbursement, billing/AR, reconciliations).
• Partner with IT and the data/AI initiatives to reduce manual effort, improve data integrity, and support scalable, multi-entity reporting.
• Operate across multiple ERP systems as needed during acquisition-integration periods.

Team Leadership

• Lead, develop, and scale the transactional accounting team (Accounting Manager and AP, AR/credit, payroll, and staff-accounting personnel); build depth, cross-training, and succession for key roles.
• Convert institutional knowledge into documented SOPs that reduce single points of failure and accelerate onboarding.
• Foster a positive, accountable, high-integrity culture across the accounting operation.

Partnership with Finance Leadership

• Partner closely with the Director of Finance / FP&A so transactional outputs feed the close, reporting, and forecasting cleanly and on time.
• Support the CFO on controls, cash, working capital, and integration, contributing to lender and sponsor reporting as it relates to transactional and balance-sheet data.

Required

• Bachelor's degree in Accounting, Finance, or a related field.
• 10+ years of progressive accounting experience, including time as a Controller (or equivalent) leading transactional accounting operations (AP, AR, payroll, GL) at a growing company.
• Demonstrated ownership of a scalable internal control environment and coordination of external audits.
• Strong ERP and systems orientation, with a track record of process improvement and automation.
• Proven people-leadership experience managing an accounting team across functions and, ideally, multiple locations.
• Excellent communication skills, with the ability to translate accounting matters for finance and non-finance stakeholders.

Preferred

• CPA (active) and/or a Master's in Accounting or MBA.
• Experience in a private equity–owned business supporting an acquisition-driven growth strategy, including accounting integration of acquired entities.
• Experience at a company with an international footprint (multi-entity, cross-border operations).
• Manufacturing or industrial exposure with inventory-intensive operations (aerospace/defense or distribution a plus); familiarity with government/defense contracting considerations helpful.
• Experience operating across multiple ERPs during integrations; Pentagon 2000SQL experience a plus.

First 6 Months— Indicators of Success

• Transactional sub-ledgers reconciled and closed on a predictable schedule, with a documented reconciliation cycle and no material audit adjustments.
• A documented, scalable control framework in place over AP, AR, payroll, and cash.
• Measurable automation of at least one high-volume manual process (e.g., payment disbursement or billing/AR).
• A repeatable accounting-integration playbook ready for the first acquisition.
• A cross-trained transactional team with documented SOPs and reduced key-person risk.

Reporting Relationships

• Reports to: Chief Financial Officer.
• Direct reports: Accounting Manager and the transactional accounting team (AP, AR / credit, payroll, staff accounting).
• Key partner: Director of Finance (FP&A Lead) — owns the close, financial and management reporting, technical accounting, and planning.