Toxic Top Performers: A Leadership Dilemma Explained

Are Toxic Top Performers Hurting Your Culture?

Every team has that standout performer who consistently delivers results. They make big sales. They acquire new customers. They get the work done in less time than others. Their numbers shine on the page. But if you ask folks what it's like to work with them, things take a different turn. You might hear: "They don't listen," "They take the credit," "They belittle others." Suddenly, that star performer isn't quite as shiny.

This is not an uncommon issue. It's very common. Some of the folks who test best on paper are the most destructive in real life. The issue isn't their behaviour. The larger issue is that they're frequently shielded, complimented, and even rewarded. Leaders might look the other way because they don't want to lose their "best" employee. However, that fear can cloud their judgment about what's happening within the team.

Actual Costs of Retaining Poisonous Talent

Let's not estimate here. Let's be specific.

A 2023 Harvard Business School study revealed that when employers retained high-performing but toxic employees, the long-term costs were larger than the short-term benefits—the costs manifested in lost collaboration, increased turnover, lower morale, and even lawsuits. One firm in the study lost three solid team members due to the presence of a "star" performer who was allowed to act poorly for too long. The outcome? It took more than six months for the trust and performance of the team to recover.

Another story is from the tech community. At a prominent startup, a lead engineer was rewarded for getting code shipped faster than everyone else. But junior employees shied away from approaching him with questions. He'd lash out at them or ridicule them in group chats. The leadership team took no action regarding the complaints for months. When the engineer finally resigned, five others followed suit — not because they particularly liked him, but because they didn't feel that leadership cared. That startup lost credibility, knowledge, and time all at once.

Why Leaders Stay Silent

So why does this occur?

One reason is that most businesses remain overly focused on performance metrics. They glance at sales reports, delivery time for projects, or client acquisition. But they don't take a hard look at how those results are being obtained. Did the individual work collaboratively or step aside from others? Did they serve the team or only serve themselves? By not asking these questions, leaders see only part of the picture.

Another reason is that leaders also get confused between confidence and value. A toxic high performer usually talks big. They present themselves as irreplaceable. And if they've been rewarded previously, they might feel they're above reproach. This makes it more difficult for others to speak up and for leaders to take warning signs seriously.

What Toxic Behaviour Does to a Team

But dismissing it has a cost.

Toxic behaviour doesn't remain contained. It spreads. It shows others that being loud, selfish, or rude is acceptable if you achieve success. It tells the respectful, quiet team members that their values don't count. That gradually builds the company culture into something toxic. People no longer contribute ideas. Trust disintegrates. The partnership goes away. Some remain quiet. Others quit.

What Real Leadership Looks Like

Now, what does a leader do about this?

First, you have to see the big picture. A top performer is not just someone who gets work done; they are someone who consistently delivers results. They're a person who makes others better, too. If somebody is crushing work but crushing others while doing it, they are not a top performer. They're a risk.

Second, you require actual feedback systems. Not annual reviews, but sincere, consistent feedback from every level of the team. Establish an environment where individuals feel comfortable sharing the truth, even if it involves someone in a position of power. If individuals are afraid to say something, that's already a warning sign.

Third, establish specific behaviour standards. Those standards should apply to all, regardless of position or performance. If a person violates those standards, they must be informed immediately and promptly. You can't wait for it to escalate. And if nothing changes, you will have to make the tough decision, even if that means losing someone who generates numbers.

You have to reward the good stuff, too. Don't only reward with bonuses or praise based on performance. Reward also those who encourage others, give credit to others, and make the team better. Incorporate kindness and teamwork into the formula for success.

You Don't Have to Choose Between Results and Respect

Here's the reality many leaders don't want to hear: holding onto one toxic employee to maintain short-term outcomes can cost you your top performers, your culture, and your sanity. Reducing them — even if it hurts initially — can be the wake-up call your team needs.

Your actual top performers are not merely the winners. They're the ones who bring others with them to win. Don't settle for anything less.