In 2013, I worked with a manufacturing company that was struggling with high employee turnover. The worst part? Leaders knew the problem they always do but did not know the root causes.

During my initial conversations with the CEO, he kept talking about one particular employee: a star performer in sales who was bringing in almost 28% of the company’s revenue. The problem? Every time his name came up in management meetings, so did complaints of team conflict, demoralization, and even allegations of misconduct. The CEO was torn. “How do I get rid of someone who is making me money?” he asked me.

Good consultants ask the questions leaders must hear, but many insiders are afraid to ask. Truth be told, that is I am usually hired. 

So, I looked him straight in the eyes and told him, “The real question is, how much is keeping him costing you and the company?” Any number of times negative one becomes negative. How does tolerating one “star performer” cost the business in the medium and long term? 

Too often, businesses cling to toxic high performers, believing their output outweighs the damage they cause. But just like a high-powered engine can destroy a poorly maintained car, these individuals erode company culture, sabotage teamwork, and ultimately weaken long-term profitability. The real cost of toxic high performers is not just in morale, it’s in financial losses, reputational damage, and missed opportunities.

The illusion of high-performance

One of the biggest lies leaders tell themselves is that revenue contribution equals business success. The sales executive I mentioned earlier was, by all traditional metrics, a high performer. He hit and exceeded his targets every quarter. But when I conducted a deeper analysis, interviewing colleagues, reviewing HR complaints, and tracking his impact beyond revenue, the reality was alarming. His toxic behavior had driven away three of the company’s most promising sales reps, costing the company nearly UGX 150,000,000 in recruitment and training. Customer complaints had increased, and internal collaboration had collapsed because no one wanted to work with him. What looked like performance was a long-term liability.

This pattern is common in many industries. Toxic high performers create a culture of fear and resentment. Their ability to deliver results makes management hesitant to challenge them. But ignoring their behavior sends a clear message to other employees: as long as you bring in money, you can do whatever you want.

How toxicity spreads like cancer

A toxic high performer is like a disease that starts small but gradually spreads to the entire organization. When I worked with a financial institution, I noticed that a senior manager was constantly belittling subordinates, dismissing their ideas, and taking credit for their work. The executive team tolerated him because he was “the guy who always delivers.” But after six months of my assessment, three key department heads resigned, citing a toxic work environment. Their departure created operational gaps that took the company over a year to recover from.

Culture is shaped by what leaders allow. If employees see that arrogance, manipulation, and intimidation are rewarded, they either adopt these behaviors to survive or leave the company. Over time, this erodes trust, kills innovation, and turns what was once a thriving business into a battleground of fear and self-preservation.

The hidden costs of keeping toxic high-performers

  1. Talent drain: Your best employees are not the ones who tolerate toxic environments, they are the first to leave. A toxic high performer can singlehandedly drive out top talent, leaving behind disengaged and fearful employees who stay only because they have no better option.
  2. Destroyed teamwork: Businesses thrive on collaboration, but toxic individuals undermine teamwork by creating division, mistrust, and unnecessary competition. A company I advised in Kenya had a high-performing regional manager whose aggressive leadership style made every other branch refuse to collaborate with him. The result? Duplication of efforts, missed sales opportunities, and constant infighting.
  3. Damaged reputation: In today’s world, workplace culture is not a private matter. Employees talk, reviews are posted online, and clients take notice. If customers perceive your business as disorganized and hostile, they will take their money elsewhere. The manufacturing company I mentioned earlier saw its brand suffer because customers started requesting to deal with other sales reps, citing the toxic sales executive’s rude and aggressive behavior.

How to fix the problem before it kills your business

The first step in addressing toxic high performers is to shift your mindset as a leader. You are not running a one-man show; you are building a sustainable business. A toxic performer may bring in short-term wins, but in the long run, they will cost you far more than they contribute.

Start by diagnosing the situation properly.

Just as a good doctor doesn’t prescribe medicine without understanding the disease, you need to assess the full impact on the individual. Look beyond their financial contribution and evaluate their influence on culture, teamwork, and long-term business health. If they are creating more damage than value, they need to go.

Next, reinforce accountability. If a toxic high performer remains untouchable, your leadership is compromised. Set clear behavioral expectations and enforce consequences. When I advised the financial institution, I recommended putting the toxic manager on a structured performance improvement plan that included behavioral metrics, not just financial targets. He refused to change, and within three months, he was replaced. Six months later, the department was outperforming all previous benchmarks without him.

Remember to rebuild what has been damaged. If toxicity has been allowed to thrive, your culture needs repair. Create safe spaces for employees to voice concerns, reward teamwork over individual heroics, and emphasize that no one is above the company’s values.

When leaders tolerate toxic high performers, they are choosing short-term gain over long-term survival. Businesses do not fail because of one bad employee; they fail because of the leadership’s inability to address the rot before it spreads. If you want to build a company that lasts, stop worshiping toxic talent and start valuing a healthy, high-performing culture. Because at the end of the day, a business that thrives on fear, division, and dysfunction will eventually collapse no matter how much revenue its star performers bring in today.

If you recognize the signs of toxic high performers eroding your company from the inside, it’s time to take decisive action. Do not let short-term gains blind you to the long-term damage. A thriving business is built on strong leadership, accountability, and a culture that nurtures sustainable success, not fear and division.

At Summit Consulting, we specialize in diagnosing business challenges, eliminating hidden threats, and transforming organizations into high-performing, future-proof enterprises. If you are serious about driving real change, strengthening your leadership, and building a company that lasts, call Summit Consulting today. The cost of inaction is far greater than the cost of making the right decision now.

Copyright Mustapha B Mugisa, 2025. All rights reserved.