Behind the Agency: A Conversation With Sumo Founder David Kelly
When people first come across Sumo Marketing Group, the questions tend to follow quickly. Are they the real deal? What drives them? What makes them different from every other agency promising results and delivering disappointment?
We thought the best person to answer those questions was the person who started it all. We sat down with Sumo’s Founder David Kelly to talk about where Sumo came from, how it has grown, and what he believes businesses genuinely deserve from a marketing agency.
David, what was the moment you decided to start Sumo — and were you nervous?
I was working at a large media agency and became frustrated with an approach that pushed solutions onto clients regardless of whether those solutions actually fitted their business or their goals. There’s also a point at which agencies get to a certain size and lose track of what the client actually needs. I believed we could do something much better.
Sumo was registered in 2019, but it was really through 2020 and into 2021 that things gained momentum. I handed in my notice in early 2021 and went full-time from around April of that year. COVID actually gave the business the push it needed to properly get going.
What did those first few months actually look like?
A lot of hard work and a lot of persistence. Cold calling, walking around industrial estates, knocking on doors, working through LinkedIn — anything to get in front of people, start conversations, and bring in clients. It was very much about building from the ground up.
What was the first thing that told you it was going to work?
Honestly, I never really entertained the alternative. Before I went full-time I was completely committed, there was no plan B. I had commercial experience, I knew how to build relationships and win business, and I simply had to make it work. That mindset carried me through the early days more than anything else.
How has Sumo changed since those early days?
Enormously. We still have clients who’ve been with us since 2020 and 2021, which says a lot, but the business has evolved significantly. We’ve found a much clearer client fit over time — businesses that need genuine help with digital transformation and online marketing, and who want a team they can actually trust to deliver it. We’ve also brought some brilliant people on board, and that has changed everything in terms of what we’re able to offer.
What does the client base look like now compared to when you started?
Very varied, which is something I’m proud of. We work across all manner of sectors, and our retention rate is genuinely strong. Some of our earliest clients are still with us, which is the best endorsement we could ask for.
At what point did you realise you needed to bring people in — and what was that like?
The business started with a freelancer and subcontractor model, which made sense at the time. But there is a natural point where you outgrow that. Taking people on in-house means better consistency for clients, stronger collaboration, and the ability to build something with real culture behind it. It also means giving people a good place to work and a career they can grow. When that tipping point came, it felt like the right and obvious next step.
Every member of the Sumo team is from the North East. Was that a deliberate decision?
It was. We are a low or no office-first agency, we come together as a team at least once a week to talk about clients and work through things properly. The majority of our clients are based in the North East, so having a team with a genuine presence and connection here makes real sense. That said, we work with businesses right across the UK — London, Kent, and plenty of places in between — so we are very much not limited by geography. But the North East is home, and that matters to us.
What do you look for when you hire?
Attitude, above everything else. Experience and professionalism matter, but you can’t teach integrity or a genuine desire to do the right thing. Because we’re a small, hands-on team, every person needs to be willing to get stuck in. When someone has that quality, everything else tends to follow.
What do you think businesses deserve from a marketing agency — and how often do they actually get it?
The barrier to entry in this industry is low. You don’t need significant capital or infrastructure to set up an agency, which means there are a lot of agencies out there who simply don’t do what they say they will. A lot of the business we win comes from clients who’ve been let down before — by false promises, by poor communication, by campaigns that were never really built around their needs.
The first thing we do is what we say we’re going to do. That alone puts us ahead of most. And then we go further, because the goal isn’t just to meet expectations but to genuinely make a difference to a business. That’s what we are about.
What is the thing you are most proud of delivering for a client?
There are genuinely too many to single one out. The moments that stay with me are not always the biggest campaigns or the headline results, they are the emails from clients who trusted us and wanted to let us know we had made a real difference, or being taken out by a client as a thank you. Those things tell you that you’ve actually meant something to their business, not just ticked a box.
What is the biggest mistake you see businesses make with their marketing?
Sticking rigidly to what they’ve always done. “We’ve always done it this way” is one of the most limiting mindsets a business can have. The clients we work with who are willing to try something new, to put themselves out there, to get in front of a camera or test a strategy they wouldn’t have considered before — those are the businesses that see real momentum. Openness makes an enormous difference.
Where do you want Sumo to be in five years?
Still growing, but in the right way. I’d love to see some of the current team progress and take on more as the business develops. But I also want to keep the small-team feel. Where clients know everyone, where we all work closely together, and where it’s genuinely a great place to be. Growth for growth’s sake has never been the point. Building something we’re proud of has always been the point.
Now You Know Us
Sumo Marketing Group was built on a simple belief: that businesses of every size deserve honest, experienced marketing support, without the inflated costs or empty promises that too often come with larger agencies. You can find out more about the team and the story behind the agency on our about us page.
If you’d like to find out what that looks like in practice, take a look at our case studies to see the results we’ve delivered for real businesses. Or, if you’re ready to have an honest conversation about your own marketing, get in touch with the team.
