An interim CFO converting to the permanent seat is not a lucky accident. It happens when the board treats the interim period as a working trial with clear success measures, and when the interim is briefed as a candidate rather than a stopgap from day one.
This is an anonymised account of a £90m turnover, PE-backed group where exactly that happened. The names and sector are disguised. The mechanics are real, and they are repeatable.
What was the situation the board faced?
The group was a multi-site services business, roughly two years into a buy-and-build. The founding CFO had scaled the finance function to a certain point, then reached the edge of their range. The board did not doubt their loyalty. They doubted whether the same person could deliver an audit-ready close, a refinancing conversation, and a credible exit narrative within eighteen months.
The CFO left by agreement. That created a gap at the worst possible moment, with a lender review due and integration of two recent acquisitions only half finished.
The operating partner made a decision that shaped everything after. Rather than rush a permanent hire under pressure, the board brought in an interim CFO to steady the function and, quietly, to be assessed as a permanent option.
Why did the board choose an interim first?
The honest reason was speed with an escape route. A permanent search under a lender deadline tends to produce compromise hires. You interview against a clock, you overweight availability, and you talk yourself into someone because you are tired of the gap.
An interim removed that pressure. The board could get a senior pair of hands in within a fortnight, protect the refinancing timeline, and keep the permanent decision separate from the crisis.
Crucially, they did not pretend the two questions were unrelated. The brief we agreed was specific. Stabilise the close, rebuild the lender relationship, integrate the acquisitions onto one ledger, and let us watch you do it.
What did the interim actually do differently?
Three things separated this interim from someone simply keeping the seat warm.
First, they treated the reporting pack as a product, not a chore. Within two months the board pack was tighter, the commentary was sharper, and the numbers reconciled. That single change bought enormous trust, because directors stop worrying about the person when they stop worrying about the numbers.
Second, they were straight about problems. When the integration revealed that one acquisition had weaker margins than the deal model assumed, the interim flagged it early with a recovery plan attached. No burying, no defensiveness. Boards remember who tells them bad news well.
Third, they built the team rather than hoarding the work. They promoted a strong financial controller, hired a capable FP&A lead, and made the function less dependent on any one person. An interim who improves the bench is thinking like an owner, not a contractor.
How did the interim become the permanent CFO?
By the fourth month the operating partner asked the question directly. The refinancing had landed, the close was clean, and the board trusted the person in the room.
We still ran a proper process. That matters. The board benchmarked the interim against external permanent candidates so the decision was evidence-based and defensible to the wider investor group. The interim knew this was happening and welcomed it, which told us something too.
The external market was strong. But the interim had a decisive advantage that no CV could match. The board had already seen how this person behaved under pressure, how they handled a bad month, and how they treated the team. That is information you almost never get from an interview.
The interim took the permanent seat, on a package appropriate to a permanent CFO, and stayed through to the eventual sale.
What made this conversion work, and when does it fail?
This worked because of four conditions. The interim was briefed as a possible permanent hire from the outset. The success measures were explicit. The board reserved the right to benchmark. And the interim wanted the job for the right reasons, not simply to extend a contract.
It fails when boards leave the arrangement vague. If nobody says whether permanent is on the table, good interims plan their exit and start their next assignment, and you lose them just as they hit their stride.
It also fails when the interim is a pure specialist. A brilliant turnaround interim is not always the right person to run a stable function for four years. Be honest about which chapter you are hiring for.
The broader lesson is simple. An interim CFO is one of the few ways to test a senior hire before you commit. Set it up deliberately and it becomes a hiring advantage rather than a holding pattern.
We structure interim mandates with conversion in mind when it suits the client. If you are weighing that route, Harper May advises boards on both the interim and permanent side, and you can see the kind of finance leaders we place on our current roles.
Common questions
Should you always tell an interim CFO the permanent role might be theirs?
Yes, if it might be. Withholding it costs you good people. Say clearly that permanent is possible, that you will benchmark externally, and let them decide to compete.
Does converting an interim mean skipping a proper process?
No. Benchmark the interim against external candidates so the decision is evidence-based and defensible to investors. A confident interim will welcome the comparison.
What if the interim is excellent but wrong for the long-term seat?
Be honest early. Some interims excel at stabilisation but are not built for a four-year build. Value the work they did and run a clean permanent search alongside.
