Deryl McKissack is no stranger to spotting toxic traits.

McKissack, 63, is the founder and CEO of Washington D.C.-based construction firm McKissack & McKissack, which she launched with $1,000 from her savings in 1990. She churned through employees who weren't the right fit in her company's early years and the business struggled, she says.

Finding the right talent helped grow her company, which now brings in $25 million per year in revenue, according to documents reviewed by CNBC Make It.

These three red flags stand out the most when McKissack is hiring employees or evaluating her current talent, she says.

People who lack integrity

Every boss needs to be able to trust their employees, McKissack says. People who lack integrity are a problem, especially managers who don't give their teams proper credit.

Alarm bells go off in her head "if someone is saying 'I did this' the whole time, and they're not giving credit to their team," McKissack says.

McKissack isn't the only person who says a lack of integrity is a red flag among employees: Heidi K. Gardner, a professional leadership advisor and distinguished fellow at Harvard Law School, similarly calls out workers who pass off other people's work as their own. It's unethical, and it gives off the impression that you don't respect your colleagues, Gardner told Make It last year.

"Maybe they're unable to actually see how much value the people around them bring to their own success," she said. "And that inability to appreciate other people's contributions is a huge red flag for me ... It's anti-collaborative."

People who are hard to be around

Nearly every team, no matter your industry, needs people who can work well with others. That's difficult when your co-workers don't like being around you, or vice versa.

McKissack says she needs to actually like her employees' personalities, because if she doesn't like to be around you, chances are, clients won't either. "If I don't want to be in their presence, then no one wants to be in their presence, usually" she says.

Having a warm, inviting personality at work can potentially take you farther in your career than your capabilities and credentials, self-made millionaire and entrepreneur Steve Adcock told Make It in April.

"Your personality will get you 10 times richer than your intelligence," said Adcock. "I learned that throughout my career, slowly but surely. I worked with a lot of smart people, no doubt about it. But those smartest people in the office weren't necessarily the ones getting the raises and promotions."

People who don't live up to the company mantra

McKissack has a three-word mantra for her business: humble, hungry, smart. She says she picked it up from author and business management expert Patrick Lencioni's book, "The Ideal Team Player."

"We have an insatiable appetite for success," McKissack wrote on LinkedIn earlier this year. "Humility drives us to make decisions for the collective good ... [and] we value emotional intelligence because we know that's what builds strong relationships."

Expecting employees to embody those three descriptors — humble, hungry, smart — turned McKissack's firm into a workforce full of people dedicated to the same mission, rather than one that struggled with low employee engagement, she says.

They're the "three virtues" of successful team players, according to Lencioni's book.

"I kept saying, 'We've been stagnant for years. Why am I stagnant?'" says McKissack. "But when I made that decision to make our mission larger than just what we do, bricks and mortar, but make it more about the betterment of mankind, is when we really started changing."

Want to stop worrying about money? Sign up for CNBC's new online course Achieve Financial Wellness: Be Happier, Wealthier & More Financially Secure. We'll teach you the psychology of money, how to manage your stress and create healthy habits, and simple ways to boost your savings, get out of debt and invest for the future. Start today and use code EARLYBIRD for an introductory discount of 30% off through September 2, 2024.

Plus, sign up for CNBC Make It's newsletter to get tips and tricks for success at work, with money and in life.