"One of the things that stands out for me when I think about what distinguishes the greatest leaders of our time, is that success is very rarely a goal for them; it's a byproduct of other goals that they have."

That's a direct quote from Adam Grant, top-rated professor at Wharton business school and author of The New York Times best-selling books "Give and Take," "Originals" and "Option B."

So if success is a byproduct of others goals, is there one defining goal that makes the world's most successful leaders stand out?

Success Linked to Helping Others

Grant expands further on CNBC Make It: "The most meaningful way to succeed is to help other people succeed.

If that's anti-climatic for you, consider the evidence. Having worked with and studied literally thousands of leaders, Grant has observed that great leaders think bigger than themselves -- they advance a vision or an idea or a project that's "going to affect a lot of people," explains Grant.

"When you do that, and align people toward a common goal, elevating their success also elevates your organization's success," says Grant.

"When you track the evidence, it tends to really work because leaders who put other people first, they end up inspiring a different kind of effort, a different level of motivation, and a greater sense of belongingness," says Grant.

"The ones that I admire the most, who also tend to produce the best results, are the ones who are givers not takers -- who say 'look, it's not all about me,'" states Grant.

Case in Point

Take the example of Kristen Hadeed, founder and CEO of Student Maid™. Earlier this year, I ranked her as one of the world's top 10 CEOs.

Consider the reasons.

In 2009, as a junior at the University of Florida, Hadeed started Student Maid™, an all-student cleaning company that has since grown into a business that has employed hundreds of Millennials.

She met leadership failure right out of the gate. When 45 of her first 60 employees quit, she realized she was the reason. "The way I was leading wasn't the right way," Hadeed said in a 2014 talk. "That's when I realized that leadership isn't a privilege to do less. Leadership is a responsibility to do more."

Now her company is known for its industry-leading employee retention rate. For cleaning companies, on average, turnover happens every two months. At Student Maid, it's two and a half years (mostly because students graduate and move on).

She built a culture of values, and everyone is expected to live up to them. She offered training that went beyond cleaning and dusting, teaching people to build great relationships with their customers and their fellow "maids" in order to provide the best possible experience for everyone.

Hadeed attributes happy customers to happy employees. She is a firm believer in the power of making employees better -- giving them purpose, freedom, ownership, and recognition -- which empowers them to do their best work.

Her first TEDx Talk, "How to Retire by 20," has received millions of hits. In it, she talks about her true passion--doing something good for other people, which explains why Student Maid cleans free for cancer patients.

Reflecting the "look, it's not about me" features of great leaders that Grant espouses, Hadeed now spends most of her time helping other organizations all over make a lasting, meaningful impact on people by creating environments where they can thrive.

Closing Thoughts

The world's most successful companies--some of which are annually featured in Fortune magazine's "100 Best Companies to Work For" list--are guided by visionary servant-leaders that Grant references from his studies. Big or small in size or revenue, whatever industry -- for profit or non-profit -- the list is long and their CEOs awe-inspiring: Whole Foods Market, Southwest Airlines, TDIndustries, The Container Store, Zingerman's, Romeo Rim, SendGrid, Driscoll's, Pencils of Promise, these employers-of-choice run on high-octane trust, leading to great engagement and astoundingly low turnover.

We have a new measure for success. As Grant poignantly states, the more leaders focus on doing something that's going to benefit others, the more likely they are to produce something that's also going to achieve success for them.