They describe genuinely different positions, with different scopes, different day-to-day realities, and different things that need to be true about the person doing them.
The confusion between the two is widespread, and it's causing real problems for businesses trying to hire, structure, and get the most out of their marketing function.
What a Head of Marketing actually does
A Head of Marketing is a senior operator. They own the marketing function end to end: the strategy, the team, the budget, and the results. They sit at the leadership table, translate the commercial goals of the business into a marketing plan, manage and develop the team that executes it, and take accountability for the metrics that matter: pipeline generated, revenue influenced, cost per acquisition.
It's a hands-on, delivery-focused leadership role. A good Head of Marketing is equally comfortable setting the annual strategy and reviewing a campaign brief. They're close to the work. Not doing all of it, but near enough to understand it, direct it, and hold the team accountable for it.
In most B2B businesses at Series A to B stage, this is the most senior marketing hire you need. Someone who can build the function properly, generate pipeline, and develop the team. That's a significant job. It doesn't need a different title to be taken seriously.
What a CMO actually does
A CMO operates at a different level. The focus shifts away from running the day-to-day marketing function and towards the longer-term, more strategic questions: how is this company positioned in its market? How does it differentiate over a three to five year horizon? What does the brand need to stand for as the business scales?
At this level, the CMO is typically a board-level participant. Not just presenting marketing results, but contributing to commercial strategy, market expansion decisions, pricing, and the investor narrative. In larger businesses, they'll have a Head of Marketing (or several) running the function beneath them, which means they're less in the detail and more in the direction.
A CMO role makes most sense when the marketing function is already working. When there's a team, a pipeline, a set of channels that are generating results, and the business needs someone to take the commercial and brand strategy to the next level.
Where the confusion causes problems
The most common mistake I see is businesses giving someone a CMO title when the role is actually a Head of Marketing. It usually happens for one of two reasons: either the title feels more impressive and seems like a way to attract better candidates, or the business genuinely hasn't thought carefully about what the role requires.
The consequences tend to play out in one of a few ways.
The person hired as CMO arrives expecting a functioning marketing engine to lead, and finds they're actually being asked to build it from scratch. That's a Head of Marketing job. Some people can do both, but it's a different skill set and a different expectation, and not being clear about it upfront is unfair to everyone.
Alternatively, the business hires a genuine CMO, someone with board-level experience and a strategic remit, into a stage where what they actually need is someone closer to the work. The CMO spends their time operating at an altitude the business isn't ready for, the day-to-day marketing function doesn't get the hands-on leadership it needs, and six months later everyone is quietly disappointed without being quite sure why.
The third version is the one I find most frustrating: businesses that treat the two titles as equivalent and use whichever sounds better in the job ad. This creates misaligned expectations before the person has even started, about seniority, about scope, about what success looks like, and about what they'll be paid.
Why getting it right matters
The title you put on a marketing leadership role isn't just semantics. It signals what you expect from the person in it, what you're willing to pay, what authority they'll have in the business, and what success looks like at six, twelve, and twenty-four months.
Getting it wrong, in either direction, creates friction that's hard to unwind. A Head of Marketing who's been given a CMO title will eventually bump into the gap between what the title implies and what the role actually allows. A CMO hired into a business that needed a Head of Marketing will either over-engineer or under-deliver, often through no fault of their own.
The honest question for any business making a senior marketing hire is: what do we actually need right now? If the answer is someone to build and run a marketing function that generates pipeline, that's a Head of Marketing. If the answer is someone to lead the commercial and brand strategy of a business that already has a functioning marketing engine, that's a CMO.
Both are valuable. Both are senior. They're just different, and being clear about which one you need before you start the process will save you a significant amount of time, money, and frustration.
A note on fractional
One thing worth adding: the rise of fractional marketing leadership has made this distinction even more relevant. A fractional Head of Marketing can give a business senior marketing leadership (strategy, team management, pipeline ownership) without the cost or commitment of a full-time hire. But it's important to be clear about what that role is. Fractional HoM is not the same as fractional CMO, and the businesses that get the most value from fractional engagements are the ones who are honest about what they actually need.
If you're not sure which applies to your business right now, that's usually a good sign that a conversation is worth having before you start writing the job description.