Your plant manager resigns with four weeks’ notice. Or your quality director goes on long-term sick leave a month before a customer audit. Someone has to sit in that chair on Monday, and you have two options: appoint an acting manager from inside, or bring in an external interim manager.
Both cover a leadership gap. They do it with a different mandate, a different cost and a different risk. This guide compares the two side by side and shows which situations call for which.
- An acting manager is an internal employee who holds the role temporarily, usually on top of their own job.
- An interim manager is an external senior expert hired for a defined period and a defined result.
- Choose acting when the job is to keep things running and a strong internal candidate already exists.
- Choose interim when the situation needs change, specialist know-how or someone with no internal ties.
What is an interim manager?
An interim manager is an experienced professional from outside the company who takes over a leadership role for a fixed period. Companies bring them in for a sudden departure, a crisis, a restructuring or a project that nobody inside has run before.
An interim manager is an external senior professional who takes a leadership role for a fixed period, with a clear mandate and a result to deliver.
- Fixed term: typically 3 to 12 months, agreed up front.
- Specialist experience: has usually done the same job in several companies before.
- Outside view: no history in the company, no internal politics to protect.
- Result-driven mandate: hired to fix, change or launch something specific, then hand over.
What is an acting manager?
An acting manager is an existing employee who temporarily steps into a leadership role. The usual reasons are parental leave, illness, a sabbatical or the weeks between a resignation and a new hire. The acting manager knows the people, the processes and the customers, so they can start on day one.
- Internal appointment: usually the deputy or the strongest person in the team.
- Continuity first: the job is to keep operations stable until the permanent leader arrives or returns.
- Short horizon: often weeks or a few months.
- Limited mandate: rarely given the authority to make big changes.
An acting manager usually keeps part of their old job. Two roles at half capacity each is the most common reason acting arrangements stall.
Interim vs acting: the key differences
| Factor | Interim manager | Acting manager |
|---|---|---|
| Who | External senior expert | Internal employee |
| Mandate | A defined result, with authority to change things | Keep operations stable |
| Typical duration | 3 to 12 months | A few weeks to a few months |
| Start | Usually within days | Immediately |
| Cost | Day rate on one invoice, no added headcount | Salary, often an allowance, plus a backfill for their own job |
| Main risk | Needs a clear brief and fast access to people and data | Overload and too little authority |
| Exit | Hands over and leaves | Returns to the old role or gets promoted |
When an acting manager is the better choice
- The absence is planned, such as parental leave or a sabbatical, and the leader is coming back.
- You already have a strong successor and want to test them in the role.
- Operations are stable: no audit, launch, relocation or customer escalation in the coming months.
- The permanent hire is signed and starts within weeks.
An acting role is also a development tool. To make it work, give the acting manager a written mandate, take part of their old workload off them and agree in advance what happens when the permanent leader arrives.
When an interim manager is the better choice
If the job is to keep the role running, look inside. If the job is to fix or change something, bring someone in from outside.
Combining both roles
The two options can work together. A setup that works well: the interim manager leads the change and coaches an internal successor, who takes over as acting or permanent manager at the end of the assignment. The company gets the result and keeps the know-how in house.
Common misconceptions about interim managers
Interim managers are only placeholders
Keeping the seat warm is the acting manager’s job. An interim manager is hired for a result: close the audit findings, stabilize the line, finish the relocation. The contract and the mandate are built around that result.
They take months to get up to speed
A good interim manager has done the same role in several companies and knows where to look first. Ask for a written plan for the first 30 days at the start. If the first weeks bring no clear picture of the situation, you picked the wrong person.
Interim is too expensive
The day rate is higher than a salary, but the comparison is not a fair one. A permanent employee is paid for about 14 months a year once you add bonuses, holidays and benefits, and works about 10. An interim manager sends one invoice for the days worked, adds no headcount, brings their own tools and needs no training. They also start within days, while a permanent hire takes months. More on the numbers in our article on interim manager salary.
How to bring in an interim manager
- Define the gap and the resultWrite down what has to be different when the interim leaves: audit closed, line running at target output, successor ready. That sentence becomes the mandate.
- Get profiles and check referencesAsk an interim provider for experts who have solved the same problem before. Check references from those projects, not general ones. Our guide on choosing the right interim lists the questions to ask.
- Give access on day oneIntroduce the interim to the team, give them access to data and systems, and confirm the mandate in writing so nobody has to guess what they may decide.
- Agree check-ins and the handoverSet a weekly review with the sponsor and plan the handover from the start. The best assignments end with a successor who can carry on alone.
How GQ Interim helps
Since 2011, GQ Interim has placed interim managers in manufacturing and automotive companies across Central and Eastern Europe, for clients such as Stellantis, Siemens, Valeo and Magna. We only recommend candidates we would choose ourselves.
Conclusion
The choice depends on what the next months have to bring. If the role only has to keep running and you have a strong person inside, an acting manager is the simpler option. If something has to change, get fixed or get launched, an interim manager brings the experience and the mandate to do it, without a long-term contract.
Fill your leadership gap this week
Tell us which seat is empty and what has to happen. We come back with profiles of experts who have done it before.
Frequently asked questions
What is the main difference between an interim and an acting manager?
An acting manager is an internal employee who covers a role temporarily and keeps operations stable. An interim manager is an external expert hired for a fixed period to deliver a specific result, such as a turnaround, a relocation or a closed audit.
How long does an interim manager usually stay?
Most assignments run 3 to 12 months. The length follows the mandate and can be extended or shortened as the situation changes.
Is an interim manager more expensive than a permanent hire?
The day rate is higher, but you pay only for the days worked, on one invoice, with no benefits, recruitment fees or added headcount. For a fixed-term job that has to show results, interim usually costs less in total.
Can an acting manager and an interim manager work together?
Yes. A common setup is an interim manager who leads the change while coaching an internal successor, who then takes over as acting or permanent manager.
Can an interim manager stay on permanently?
It happens, but it is the exception. Most interim managers prefer project work and plan their exit from the start. If you want to keep someone, agree on it openly with the interim provider.
Can an acting manager hire, fire or sign contracts?
Only within the authority the company gives in writing. Acting managers usually keep day-to-day decisions and escalate hiring, dismissals, investments and major contracts to their own manager. An interim manager gets these powers in the mandate when the task requires them, for example in a restructuring.
Is an interim manager more senior than an acting manager?
Not by title, because both hold the same position for a time. The difference is experience and mandate: an interim manager is usually a senior executive who has done the role in several companies and is brought in to change something, while an acting manager is an internal colleague who keeps the role running.
How is an interim manager engaged compared with an acting manager?
An acting manager stays an employee under their existing contract, often with a written appointment and an allowance. An interim manager is engaged through a service contract, for example with a provider such as GQ Interim, is invoiced for days worked and does not become your employee.
Should an acting manager get extra pay?
Usually yes, when the role is covered for more than a few weeks. Common practice is a temporary allowance for the period, agreed in writing together with the scope of authority and what happens when the permanent manager arrives.
