First, check you should be hiring at all
The honest test before any req goes out: do you have a growth system that needs an owner, or a growth task that needs a doer? A system, revenue flowing, multiple channels, a funnel worth optimising, justifies the seat. A task justifies a specialist, and a Head of Growth hired to do a specialist's job leaves within a year. Most companies reach for this role about a year too early or a year too late, and if you are pre-product-market-fit you are early: once your product is habit-forming, then and only then does the growth seat pay for itself.
If the system is real but the budget is not, the answer is usually a fractional Head of Growth rather than a cheaper full-time hire. A junior person with a senior title is the most expensive option on the menu.
Where the good ones actually are
The best people in growth are often stubborn and not open to work, so the search is a sourcing problem, not a filtering problem. When I mapped the Australian market for my own referral purposes I found 15 genuine growth generalists, of whom I would rate three at 95 out of 100. That is the size of the real pool. Job ads reach almost none of it, which is why knowing who is actually good in Australia matters more than writing a better ad.
Network effects dominate here. The best link builder I ever hired, Christian Somcio, around whom I scaled a team of 12 at ContactOut, came through an introduction from Canva's first Head of Growth. The good people know the good people, and one strong referral beats a hundred applications. Recruit the referrers, not just the candidates.
What to test for
Test for a documented number and the ability to explain it honestly. Ask what they grew, from what to what, over how long, and what they would discount from the claim. Operators volunteer the caveats: the seasonality, the price change that helped, the channel that was already working. Theatre answers are all lift and no context. Then test breadth with a real scenario from your own funnel, and watch whether they reach for one favourite channel or reason across several. The role is a portfolio job, which is the core of how it differs from a CMO.
Pay them properly, the bands are on the salary page, and judge the first quarter against a realistic 90-day arc rather than a hockey stick. The full scope of what you are hiring for is at what a Head of Growth actually does.
Two more references worth having open while you interview: how a real experiment queue runs, which is what your hire will actually operate day to day, and the statistical honesty bar their claimed results should clear.
FAQ
When should a startup hire a Head of Growth?
After product-market fit, when there is a growth system that needs an owner rather than a task that needs a doer. Hired earlier, they optimise a leaky product. Hired later, they inherit calcified channels. Both failure modes are common.
What should I ask a Head of Growth candidate?
What they grew, from what to what, over how long, and what they would discount from their own claim. Real operators volunteer the caveats. Then give them a scenario from your actual funnel and watch whether they reason across channels or default to a favourite.
Should I hire full-time or fractional?
Below about 30 people, fractional usually wins: senior attention on the growth number without the $200k+ all-in cost. Go full-time when the coordination cost of part-time leadership exceeds the salary gap.