The hire you cannot justify yet
Leadership teams at Series B and C companies often face the same problem. AI is becoming relevant across the business. The CEO wants a plan, the CTO has no spare capacity and the board keeps asking who owns the work.
Hiring a Head of AI looks like the obvious answer. In practice, a credible senior leader costs £250k plus, takes six to nine months to find and needs another three to six months to get up to speed. The company may not even know what the role should own until that person arrives.
Most businesses at this stage need something different: senior judgement, a coherent roadmap and someone who can put production systems into use while the internal team develops. That is the job of a Fractional Head of AI.
What a fractional head of AI actually does
The role combines four responsibilities under one senior owner.
AI strategy
The plan should connect to board-level KPIs. A list that says "ChatGPT for marketing, Claude for product and Copilot for engineering" is a procurement list, not a strategy.
Start with the business. Which three to five processes could move the metrics the board cares about if AI automated or accelerated them? Then define the technical approach, the order of work and the 12 month plan. That is the level of detail the board needs.
Architecture and stack
Choosing the wrong stack early can create an expensive rebuild 18 months later. Growth-stage companies often default to whatever the CTO used in a previous role or the product pitched by the first persuasive vendor. Neither is a sound selection method.
A Fractional Head of AI chooses technology against the use cases. That might mean n8n or a similar platform for orchestration, different frontier models for different jobs, vector stores where they add value and ordinary SaaS where specialist infrastructure is unnecessary.
Hiring and mentoring
A good fractional leader works towards becoming unnecessary. They write the job description for a full-time successor, join the interview panel, onboard the new hire and hand over ownership cleanly. Along the way, they mentor internal AI engineers, data scientists and functional leaders who are introducing AI into their teams.
The aim is that, after 12 months, the company has a full-time Head of AI who can be effective on day one because the foundations are already in place.
Hands-on delivery
Advice alone does not change an operating result. A Fractional Head of AI should also build customer support automation, document pipelines, internal tools and finance workflows. Combining senior direction with delivery is what separates the role from a conventional adviser.
At Healf, the FT's #1 fastest-growing company in Europe, this approach drove 85% daily AI tool adoption across the company. Adoption reached that level because the systems were built around the team's work and then put into use.
Inside PE portfolios, the same logic is now arriving from the fund side. In our conversations with funds this year, several are converging on a fund-embedded head of AI: one senior owner who scopes priorities across the whole portfolio and buys build capacity externally, rather than each portfolio company attempting its own hire.
When fractional beats full-time
Three conditions usually point towards a fractional model.
Stage: Series B to D
If AI matters to the business but is not the product itself, and the company has 50 to 300 people, fractional leadership is often the right size. Once AI sits at the centre of the product, or the business grows beyond 300 people, the scope can justify a full-time role.
Budget: a £250k plus hire does not yet make sense
A typical fractional arrangement covers 1 to 2 days per week. It is priced around the output rather than the full-time equivalent, giving the company access to senior judgement without taking on the full permanent cost.
Speed: the company needs progress within 90 days
A full-time search takes at least six to nine months. Fractional leadership is the practical option when the board expects a plan and working output during the next quarter.
When full-time is right
A full-time role usually makes sense at Series D plus or before an IPO, particularly when AI has enough scope to occupy one senior person continuously.
It is also the right choice when the product itself is AI. In that case, the Head of AI is closer to a co-founder-level appointment and a fractional arrangement will not provide enough ownership.
Finally, a search is easier to justify when the executive team already knows exactly what the role should deliver and can assess the likely return.
When interim makes sense
An interim leader works full-time for 6 to 12 months while the permanent search runs. This suits a company where the AI remit is already full-time but senior ownership cannot wait for the new hire.
Interim costs more than fractional because it is a full-time commitment. The people who take these roles also tend to specialise in stepping into established functions rather than building one from the beginning. Most growth-stage companies do not yet need that model.
How to structure a fractional engagement
The arrangements that work usually cover 1 to 2 days a week, with a minimum quarterly commitment and monthly payment. The quarterly minimum gives the leader enough time to put working systems into production. Shorter, hourly arrangements tend to produce advice without delivery.
Fees usually sit at 30 to 50% of the equivalent full-time cost and should be judged against outputs rather than hours.
Next steps
If you are a CEO or CTO deciding between fractional and full-time AI leadership, book a 30 minute call or read more at /fractional-ai-lead.