In short
A COO runs the operating business with line responsibility and sits on the executive team. A chief of staff is a staff role without a function of its own that steers the leadership’s agenda, priorities and decisions. You need a COO when operations need their own leader, and a chief of staff when the top has more initiatives than it can steer itself. The COO job is often a step towards CEO; the chief of staff role usually lasts two to three years.
Key takeaways
- The COO owns the operating business and leads functions; the chief of staff has no line of their own and works with borrowed authority.
- About a third of large US companies have a COO: on average 35.8% of Fortune 500 and S&P 500 companies between 2016 and 2026.
- In an analysis of 563 listed companies across 19 European countries, about 30% had at least one chief of staff.
- The COO job is often the last step before CEO: 44% of sitting CEOs of large US companies were COO or president immediately before.
- A COO is no guaranteed success: a ten-year study found that CEOs with COOs delivered lower company performance on average than those without.
- Decide by the problem: if operations lack leadership, hire a COO; if the top lacks steering, hire a chief of staff.
Chief of staff vs COO at a glance
Both roles work closely with the CEO, and both titles are used in very different ways. The difference lies in the mandate: the COO leads, the chief of staff steers.
| Aspect | Chief of staff | COO |
|---|---|---|
| Core mandate | Steer the leadership agenda, priorities and decisions; follow up on initiatives | Run the operating business and deliver results |
| Authority | No line of their own, borrowed authority | Line responsibility for functions and teams |
| Position | Staff role, usually not on the executive team | Member of the executive team or board |
| Typical background | Economics, finance or consulting | Operational leadership, mostly inside the company |
| Typical tenure | Usually two to three years | Open-ended, often a step towards CEO |
What does a COO do?
A chief operating officer runs the day-to-day business, depending on the set-up for example delivery, supply chain, sales or service. The COO leads function heads and is measured on operating results. How much the role varies is shown by Nathan Bennett and Stephen Miles, who distinguish seven types, from the executor who frees the CEO for external work, through the change agent for restructurings and the mentor for a young CEO, to the heir apparent. They name a high level of trust between CEO and COO as the most critical success factor (Bennett and Miles, 2006; Georgia Tech, 2006).
The role is common in large companies, but far from universal: between 2016 and 2026, on average 35.8% of Fortune 500 and S&P 500 companies had a COO; in 2026 it was 254 out of 665. Of the new COOs appointed in 2026, 84.6% were internal promotions (Crist|Kolder Associates, 2026).
What does a chief of staff do?
A chief of staff sets the leadership’s priorities, prepares decisions, steers selected cross-functional initiatives and makes sure decisions are implemented. Formal people management plays hardly any part in the day-to-day job (Zhou et al., 2024). In an analysis of 563 listed companies across 19 European countries, about 30% had at least one chief of staff, typically for two to three years (Gigante, Rella and Cerri, 2026). More in Hiring a chief of staff.
What research says about both roles
For the COO there is a well-known long-term study. Donald Hambrick and Albert Cannella analysed a large ten-year sample. CEOs who lacked operational experience or experience in the firm were more likely to have a COO. At the same time, they found a substantial negative association: CEOs with COOs delivered lower company performance on average than those without (Hambrick and Cannella, 2004). That is an association, not proof that a COO does harm, but it shows the role is no guaranteed success.
For the chief of staff, comparable data on company performance are missing. Research on the role is still at an early stage (Zhou et al., 2024).
Chief of staff or COO: which role do you need?
- A COO when the operating business needs its own leader: several sites, plants or countries, an organisation that can no longer report directly to the CEO, or a CEO who is mainly busy outside the company.
- A chief of staff when the top has started more initiatives than it can follow up itself: after a CEO change, in a transformation, or with a value creation plan after a buyout.
- Both in larger organisations. A COO can have a chief of staff too; in a member survey of the Chief of Staff Association, the highest salaries went not to chiefs of staff to CEOs but to those working for a COO or another C-suite member (Chief of Staff Association, 2023).
A rule of thumb from our practice: ask which problem should be solved in twelve months. If the answer is “delivery, cost, quality”, look for a COO. If it is “our five most important initiatives are on track and the top team pulls in one direction”, look for a chief of staff. For individual projects in a start-up, a founders associate is often enough.
From chief of staff to COO?
The chief of staff role has long been seen as transitional, with many moving on to a leadership job in operations or strategy (Chief of Staff Association, 2023). The path to COO is possible but not automatic: a COO needs experience in operational leadership, which a chief of staff without a line of their own usually still has to gain. The COO job, in turn, is often the last stop before CEO: 44% of sitting CEOs of Fortune 500 and S&P 500 companies were COO or president immediately before, most of them inside the same company (Crist|Kolder Associates, 2026).
Frequently asked questions
What is the difference between a chief of staff and a COO?
The COO runs the operating business with line responsibility and sits on the executive team. The chief of staff has no function of their own; they steer the leadership’s agenda, priorities and decisions and work with borrowed authority.
Is a chief of staff a deputy CEO?
No. A chief of staff does not formally deputise for the CEO and runs no function. They prepare decisions and follow up on them; the decisions are made by the leadership.
How many companies have a COO?
About a third of large US companies in the Fortune 500 and S&P 500: on average 35.8% between 2016 and 2026, and 254 out of 665 companies in 2026 (Crist|Kolder Associates, 2026). We found no comparable analysis for Germany.
Can a chief of staff become a COO?
Yes, but not automatically. Many chiefs of staff move on to a leadership role in operations or strategy. For a COO job, they often still lack experience leading operations with a line of their own.
Does a start-up need a COO or a chief of staff?
It depends on the problem. If the growing operation lacks leadership, a COO; if the founders have more initiatives than they can follow up, rather a chief of staff. For individual projects, a founders associate is often enough.
Sources
- Crist|Kolder Associates. (2026). Volatility Report 2026: C-Suite Trends and Insights. America’s Leading Companies., Crist|Kolder Associates (2026). Annual report by a US search firm on CEO, CFO and COO changes in 665 Fortune 500 and S&P 500 companies, data through 31 July 2026; read as PDF. Cited for the share of companies with a COO (average 2016 to 2026: 35.8%; 2026: 254 sitting COOs), the share of internal appointments among new COOs in 2026 (84.6%, partial year) and the immediate previous position of sitting CEOs (COO or president: 41.3% internal, 2.7% external). Only executives with the exact title chief operating officer count as COO. US companies only.
- Hambrick, D. C., & Cannella, A. A. (2004). CEOs who have COOs: Contingency analysis of an unexplored structural form. Strategic Management Journal, 25(10), 959–979., John Wiley & Sons (2004). Peer-reviewed study based on a large ten-year sample. The abstract was read, not the full text. Cited for two findings: CEOs who lack operational experience or experience in the firm are more likely to have a COO; CEOs with COOs delivered lower organisational performance on average than those without. An association, not proof of cause.
- Bennett, N., & Miles, S. A. (2006). Second in command: The misunderstood role of the chief operating officer. Harvard Business Review, May 2006., Harvard Business Publishing (2006). Full text behind a paywall; title, authors and issue checked. The seven COO types and trust as the most critical success factor are cited as summarised by Georgia Tech (2006).
- Georgia Institute of Technology. (2006). Researchers demystify role of COO in new book. Mercury., Georgia Institute of Technology (2006). News release on the book “Riding Shotgun: The Role of the COO” and the HBR article by Bennett and Miles. Cited for the seven COO types and the statement that a high level of trust between CEO and COO is the most critical success factor.
- Zhou, S., Hiller, N. J., Zaccaro, S. J., Campbell, L. N. P., McCauley, R., Parris, T., & Klimoski, R. J. (2024). The corporate chief of staff: Strategic leadership influence from outside the spotlight. Journal of Leadership & Organizational Studies, 31(3), 289–303., SAGE (2024). Peer-reviewed exploratory study, read in full (author version). Data: 2,500 LinkedIn profiles of US-based chiefs of staff, a survey of 108 chiefs of staff and 13 interviews; mostly self-reports. Cited for the tasks of the role, the minor part formal people management plays, and the finding that research has so far barely studied the role. No claims about effects on company results.
- Gigante, G., Rella, S., & Cerri, A. (2026, June 16). An invisible facilitator improving decisions: The Chief of Staff gains ground in Europe. SDA Bocconi Insight., SDA Bocconi School of Management (2026). Article on a study by SDA Bocconi (I.C.E.): 753 chiefs of staff in 563 listed companies across 19 European countries. Cited for prevalence (about 30%), background (over half economics or finance, about 28% consulting) and time in role (around two to three years). Germany is not reported separately; over 50% of the positions found are in financial services.
- The Chief of Staff Association. (2023). State of the Industry Report 2023., The Chief of Staff Association (2023). Anonymous online survey of 292 members (July to August 2023), not a representative sample. Cited for the finding that the highest salaries went not to chiefs of staff to CEOs but to those working for a COO or another C-suite member, and for the long-held view of the role as transitional, usually followed by operations or strategy (sub-pages “Factors Affecting Chief of Staff Compensation” and “Pathways into the Chief of Staff Role”).