Balderton 
- 15 July, 2026
Finding the right CoS is not just about assessing qualifications, it is about finding someone you feel comfortable spending a lot of time with. This person will be in your most sensitive meetings, travelling alongside you, and speaking to you multiple times a day. The interview process needs to reflect that.
Start with your problems, not a job description
If you worked through the problem mapping in part one and the qualities framework in part two, you already have the foundation of your job specification. The bottlenecks you identified and the work that keeps landing back on your plate is your starting point. You are not writing a generic list of CoS responsibilities, you are describing the specific work that needs to happen in your company right now.
The most common mistake is only thinking about the role today. Spend time reflecting on how the business will change in the next twelve months and how that shapes what you need from this person. For example, if you are hiring fast and scaling a team, you will need someone who jumps into the process, builds the operating cadence and keeps the leadership team aligned. The role expectations should reflect where you are going, not just where you are.
How to structure the interview process
The structure of the interview process will differ depending on your expectations for the role, but include the following:
An informal conversation. You, as the founder, should spend time with the candidate in a low-pressure setting, before jumping into any structured assessment. You will know within the first conversation whether the energy and dynamic feels right.
Involve your team. The CoS will work across your whole organisation, not just with you. Get two or three key team members to meet the candidate. You want to know that they can build rapport and communicate well with people beyond you.
A case study. Give candidates a real problem you are facing right now in the business. It is not necessarily about getting the right answer, but assessing how they think, how they structure ambiguity and communicate their reasoning.
Consider a personality assessment. Tools like TestGorilla are worth using, not to filter candidates out, but to understand how your working styles map onto each other. Knowing where you naturally complement each other and where friction might emerge is useful context before you commit.
How to assess a Chief of Staff candidate: Trust, EQ and working style
The most important thing you are assessing in this process is whether you can genuinely trust this person and whether they have the emotional intelligence to represent you and your business in many different scenarios. Test for emotional intelligence by presenting a situation they will genuinely face in the role. For example, a senior leader comes to them frustrated about a decision you made and asks them to weigh in. How do they handle it? Do they stay neutral and bring it back to you, or do they take a side? They need to reduce complexity, not add to it.
It’s also important to consider your working style. How do you communicate, how often do you want updates, how do you work under pressure? Lay this out explicitly and ask candidates the same. Then ask the inverse, when have they worked in a way that didn’t suit them? You want someone who is genuinely self-aware about how they partner, not just someone who can perform well in an interview room.
Leah’s view on why CoS hires fail is clear: “It’s almost never about skill set. It’s about communication and chemistry. The CoS and the founder just weren’t the right match. The role requires significant time together, close alignment, and matched energy and cadence.”
The case study
This is a critical part of the CoS interview process to assess how a candidate approaches problems, and communicates them.
A good case study might look something like this: “We are three months away from a Series B raise. The CEO is spending around 60% of their time on investor conversations and board preparation. In the meantime, the leadership team is misaligned on Q3 priorities and two key hires have stalled. How would you approach the next 90 days?”
That kind of prompt has no single right answer. It requires the candidate to make judgment calls about prioritisation, ask clarifying questions about context, and communicate a clear recommendation. That is exactly what the CoS will be doing in the role.
One final thought
Hiring a CoS should enable you to effectively double what you can do. This is someone who will represent you and your business in rooms you cannot always be in, so take the time to get it right. Be honest with yourself about your strengths and weaknesses, invest in finding genuine fit, and give that person real access and authority from day one.
It is also worth noting that the CoS role is not a fixed one. The best CoS hires grow with the business, often transitioning into a senior functional role. The founders who get the most from this hire are the ones who think about that trajectory from the start, and invest in the person as much as the role.
