What is a COO?

A Complete Guide to the Chief Operating Officer Role in 2025

A candid conversation about the most ambiguous role in the C-suite.

The Chief Operating Officer (COO) role remains one of the most misunderstood positions in the C-suite. Unlike other executive roles with clear-cut responsibilities, the COO position varies dramatically between companies, making it challenging for both organizations and professionals to define what a COO actually does.

What is a COO? The Essential Definition

A Chief Operating Officer is a senior executive responsible for overseeing the day-to-day operations of a company and executing the CEO's vision. However, this basic definition barely scratches the surface of what modern COOs actually do.

According to COO expert Davinia Knowles, who founded the London COO Roundtable and has coached numerous operations professionals, the role can be understood through three key elements - what she calls the "3 Rs".

The COO Role: It's Complicated (And That's Actually The Point)

Here's what makes the COO role so tricky to pin down - every single one is different. As Davinia put it: "Every COO that I met had a completely different job description to me, so I couldn't quite really benchmark what I was supposed to be doing with what others were doing."

But here's the thing that really clicked for me in our conversation: this isn't a bug, it's a feature.

"I normally encourage the COOs that I work with to sort of start developing their own mental model of COO for themselves in the place that they're in with the people they're working with," Davinia explained.

The role changes based on:

• Company size and stage

• The CEO's profile and preferences

• What the business actually needs right now

The 3 Rs of COO Success

1. Remit The biggest version of the COO role operates across the whole company with cross-functional responsibilities. COOs work "on the business" rather than just "in the business," giving them a holistic view of the organization alongside the CEO.

2. Relationships Successful COOs develop prerequisite relationships across all levels - from board members and the CEO to C-level peers and functional leads throughout the organization. This relationship-building ability makes them credible influencers across the business.

3. Responsibility COOs typically have functional responsibility, though the specific functions vary dramatically depending on company needs, stage, and the COO's strengths and experience.

The 5 Types of COOs in Modern Organizations

We dove into Alison Pickens' famous article about four types of operations professionals, but agreed there's actually a fifth emerging:

1. Chief of Staff COO

• Role: Extension of the CEO with no direct reports

• Best for: Smaller businesses and seed-stage companies

• Focus: Strategic support and CEO capacity expansion

2. The Operator COO

• Role: Runs the entire business while CEO focuses externally

• Best for: Companies with visionary CEOs who prefer evangelizing over operations

• Focus: Total business operations and execution

3. The Operational Strategist COO

• Role: Acts as organizational "glue" and implements scalable processes

• Best for: Companies experiencing misalignment across teams

• Focus: OKR processes, data systems, IT infrastructure, and cross-functional coordination

4. Chief Customer Officer COO

• Role: Owns the complete customer journey from marketing to delivery

• Best for: Companies needing unified go-to-market execution

• Focus: Sales, marketing, customer success, and revenue operations

5. Product & Development COO

• Role: Leads product and R&D while scaling broader business operations

• Best for: Technical companies needing product-focused operational leadership

• Focus: Product development, engineering operations, and technical team alignment

COO vs Other Executive Roles: Key Differences

Understanding the distinctions between similar roles helps clarify when you need a COO:

COO vs Chief of Staff

• COO: Has functional responsibility and direct reports

• Chief of Staff: Typically no direct reports, focuses on strategic support and research

COO vs VP of Operations

• COO: Operates at executive level as peer to other C-level executives

• VP of Operations: Usually operates below executive level with more limited cross-functional authority

COO vs "Systemically Squashed" Roles

Some organizations inadvertently limit COO effectiveness by:

• Relegating them to back-office functions only (Chief Admin Officer)

• Preventing true executive-level influence and relationships

• Limiting cross-functional authority

When Does Your Company Need a COO?

"At what stage should a CEO start to be thinking about bringing in a COO?"

This question comes up constantly, and here's what we learned: it's not really about company size.

Some VCs say don't hire a COO until Series B or 120+ people. But I've seen COOs join successfully at 40-45 people when the focus was on building repeatable go-to-market engines before the bigger scale phase.

Company Stage Considerations

While some VCs suggest waiting until Series B or 120+ employees, successful COOs often join earlier when:

• The business model is operationally complex

• The CEO needs a partner for scaling repeatable processes

• The company is preparing for significant growth phases

CEO-Driven Factors

COOs are often hired when:

• The CEO prefers external-facing activities over operations

• The founder needs an "heir apparent" for eventual transition

• The CEO wants a trusted advisor and thinking partner

• Operational complexity exceeds what one person can manage

"You run into trouble when you have an organisation that thinks it should be scaling and it's not. They bring a COO in and that COO is experienced and then is bored because they kind of sat there with nothing really to do."

The COO-CEO Partnership: Making It Work

"I always feel like as a COO... I've had two marriages for most of my career, so the one that I work on at home and then the one with my CEO, and it takes almost as much effort as the whole marriage."

This quote really stuck with me because it captures how intense and important this relationship is.

The most common reason COO hires fail? The relationship with the CEO doesn't work. Not the person's competence, not their experience - the relationship.

Davinia's advice for COOs struggling with their CEO relationship:

Contracting and Trust

• Regular conversations about roles and expectations

• Clear agreement on decision-making authority

• Full remit to operate across all business functions

• Psychological safety to challenge and provide input

Complementary Strengths

The most effective partnerships leverage different time horizons:

• COO: 6 months to 2 years (architectural thinking)

• CEO: 2+ years (visionary thinking)

• Operators: Present to 6 months (execution focus)

Values Alignment

COOs must share the underlying values of the CEO and organization, especially regarding people and culture decisions.

Measuring COO Success

"How are these roles actually crafted around these people and these experienced sort of professionals? And how do you measure success?"

This is where it gets interesting. Unlike sales (clear numbers) or product (launches), COO success is often invisible.

One CEO put it perfectly: "If I'm successful, what happens? The company hits its goals and its numbers."

That's it. Your success is the company's success.

But here's what I loved about this perspective: "COOs can be propositional. You know, and actually talk about what they want their role to be and kind of put it out there that this is a powerful role and how they want it to come into fruition in the business."

You're not just a "garbage man" cleaning up everyone else's problems. You're not taking on "everything that nobody else wants to do." You're thinking strategically about what variables need to be solved to get the company to the next level.

COO vs. Chief of Staff vs. VP of Operations: The Real Differences

This comes up constantly, so let's clear it up:

Chief of Staff vs. COO: Chiefs of staff typically don't have direct reports or functional responsibility. They're more strategic support and research for the CEO. COOs have functional responsibility and are influencing across the organization.

VP of Operations vs. COO: VPs of Ops might not be true peers to the C-level team. COOs sit "slightly above the exec" and have that broader remit to operate everywhere.

Sometimes people get the wrong title. Davinia mentioned having people in her roundtable who were labeled "chief of staff" but were actually doing COO work: "They start talking about the fact that they do have functional responsibility. Actually, they are working cross functionally across the org. They are influencing."

The Identity Challenge

One thing that really resonated was this idea of COO identity. Some people love being a COO and embrace the power of the role. Others never quite make the transition from their previous identity (CTO, CRO, etc.).

"Some people love the identity of being a COO. They embrace it, they love it, they realise how powerful and potent that role can be. And others don't."

If you're moving into a COO role from another function, you have to actually want to be a COO - not just be doing it temporarily until you can get back to your "real" role.

The Introvert Advantage

Here's something I didn't expect: "Lots of COOs that I've met are quite introverted. There's something about that servant leadership role. Being slightly in the back, not having to be the person who's out there in the spotlight."

This actually makes sense. COOs often succeed through one-on-one relationships, listening more than talking, connecting people and ideas. You're the glue that holds things together, often working behind the scenes.

Embrace the Ambiguity

"The power in the COO role is about the difference. The difference in the role and the ambiguity in the role causes, I think that's the power in it. And if you can really embrace that, then you can be a very authentic COO in your own right and be very powerful."

The fact that every COO role is different isn't a problem to solve. You get to craft it around what the business needs and what you're uniquely good at.

Instead of trying to fit into some predetermined box, the best COOs figure out how to use their strengths to solve their specific company's operational challenges. That ambiguity that frustrates everyone?

That's actually your superpower.