The Gospel is not that the “Good are in and the Bad are out.” The Gospel is that the “Humble are in and the Proud are out.” - Tim Keller
Until we are ready to admit that “High-Performing-Egomaniacs” are a serious threat to a company’s culture and results, there is no hope of creating a redemptive workplace.
Why is an employee with an overblown ego so destructive to the company culture? Because although they may make their own wallets bigger; they create misery for everyone else along the way, they demotivate and lower the results of all those that must interact with them and they undermine your leadership credibility. When as a manager you fail to address an overblown ego, people know that you value the results of the bully more than you value the souls and the results of everyone else.
Results matter. Values matter too. Don’t fall into the false dichotomy of thinking you must choose one above the other. Choose both for yourself and expect others to follow you.
What to do with the “High-Performing Egomaniac?” Have one or two serious performance reviews with the individual. Give them the coaching they need. Let them know you value them as a person first and that you appreciate their results as well. But you need to draw a hard line. You will not let their results blind you to the souls they are killing every day in the organization. Describe in stark, specific terms, the devastation their behavior creates. Make sure they know you are serious, “that the Proud are out.”
If after a few months the behavior persists, terminate the Proud. The Humble will thank you.