Cameron Herold breaks down seven COO archetypes from Nate Bennett and Stephen A. Miles' research: executor, change agent, mentor, other half, partner, heir apparent, and MVP. A COO's role isn't fixed tasks but what the specific CEO needs, and one person can shift between multiple types over time.
Chapters
Nate Bennett and Stephen A. Miles wrote a great book on COOs, Riding Shotgun, and also a widely read Harvard Business Review article titled "The Second in Command: The Misunderstood Role of the Chief Operating Officer." They describe the COO's role as at once so critical and so situational. They go on, while other jobs are primarily defined in relation to the work to be done and the structure of the organization, the COO's role is defined in relation to the CEO as an individual. After interviewing dozens of CEOs and COOs, Bennett and Myles arrived at 7 main categories of COO depending on the role the CEO needs the COO to fill: executor, change agent, mentor, other half, partner, heir apparent, and MVP. Of course, a COO can belong to more than one category at the same time or evolve over time.