Fractional CFO | High-Growth B2B SaaS Scale-Up | London

The Client

Harmonic are delighted to be supporting a high-growth B2B SaaS business following a successful funding round. The company is experiencing rapid commercial expansion, with ARR anticipated to more than double within the next 12 months.

With a strong product offering and an ambitious leadership team, the business is now entering its next phase of scale and requires experienced financial leadership to elevate reporting, support strategic decision-making, and meet increased investor expectations.

This is an opportunity to join a collaborative, low-ego environment made up of talented technologists and operators, working from a modern office.

The Role

Our client is seeking an experienced CFO or Finance Director to work closely with the CEO and leadership team on a part-time basis (circa 1 day per week).

The company already has a strong Financial Controller managing day-to-day finance operations, they require a senior finance leader to professionalise forward-looking finance, improve FP&A capability, and enhance board-level reporting following their recent funding round.

The successful candidate will bring both strategic oversight and a hands-on approach, supporting the business through its next stage of growth while building scalable financial processes. Initially, there may be a requirement for increased involvement during onboarding to accelerate impact and ensure a smooth transition.

Key Responsibilities

• Provide strategic financial leadership to the executive team and investors
• Elevate FP&A capability, including forecasting, modelling, and performance analysis
• Improve quality and structure of board reporting and investor materials
• Partner with leadership on commercial decision-making and growth planning
• Support and mentor the Financial Controller
• Maintain oversight of accounting, reporting, and financial controls
• Lead improvements to financial processes and systems as the business scales
• Support R&D tax credit processes and wider finance projects where required
• Deliver a clear financial "health check" and roadmap for finance maturity

What We Need to See (Essential)

• Proven experience operating as a CFO or Finance Director within a scaling business
• Background in B2B SaaS environments.
• Experience supporting businesses through Series A - C growth stages
• Strong FP&A and investor reporting expertise
• Ability to operate both strategically and hands-on when required
• Confident working within founder-led, fast-paced environments
• Strong stakeholder management skills with non-finance audiences
• Enjoy working closely with product and technology teams
• Be comfortable operating in a scaling, evolving environment

Day Rate: £800-£900 per day

Location: London Bridge, in office 1 day per week.

Length of Contract: 6 months

Start Date: ASAP

If you are interested - to be considered for the role please apply. Any questions please send through

At Harmonic, we are dedicated to fostering an inclusive and equitable workplace. We actively welcome applications from individuals of all backgrounds and assure you that every candidate will be thoughtfully considered for the roles we represent, without regard to race, religion, gender expression, disability, or sexual orientation.