✒ An executive chair is a hybrid position, having substantial oversight, strategic and board leadership responsibility at the same time.

Executive board chair is typically a former leader of the firm — such as founder (e.g. Jeff Bezos at Amazon), member of founding family (e.g. Bill Ford at Ford Motor), or retired CEO (e.g. Eric Schmidt at Google). Accordingly they have considerable knwoledge about their companies.

Corporate governance best practices typically prescribe a division between management and oversight. For that reason, companies have been moving away from a combined CEO-chair structure and toward an independent chair structure. 

The executive board chair position offers a middle-ground option, seeking to benefit from a chair’s strategic acumen and managerial experience while still remaining independent from management to provide effective oversight.

It is indeed effective: A research studied S&P 1500 companies from 2002 to 2020  found that when a company has an executive board chair, it has on average a 33% higher profitability than when it has another type of board chair.