I’ve been a full-time student and teacher of leadership for the past 30 years. I’ve coached and been coached by everyone from high school seniors to Fortune 100 CEOs. The most common question I get, no matter whom I’m coaching, is this:

“What’s the most important quality in a great leader?”

I’ve probably been asked that question hundreds and hundreds of times. To be honest, I struggled with it for a while. There are so many qualities that are non-negotiable if you want to be a heart-led leader. Integrity. Character. Authenticity. Accountability. The list goes on. But over the years, I’ve gotten to know some of the greatest leaders in the world. Not just CEOs and other titans of industry, but teachers, general managers, and government workers. Doctors, nurses, lawyers, engineers, and soldiers. No matter what you do, how many people you lead, or how much money you make, the single greatest quality in a leader is this: 

Humility.

That might not be the first trait that comes to mind. When you consider the world’s great leaders, you think of attributes like vision, courage, charisma, and boldness. These are important traits, yes, but they will only get you so far. The CEOs of Blockbuster, Nokia, Blackberry, Kodak, and Circuit City were charismatic. They were bold. They had vision. But they lacked humility. They lacked the ability to solicit feedback from others. To realize they weren’t the smartest folks in the room. To acknowledge that maybe they needed to hear some innovative ideas, admit to some mistakes, and change course before it was too late.

Some people will say that once you reach a certain level of success, humility is impossible. It’s easy to be humble when you don’t have massive responsibilities, when you aren’t in charge of thousands of people, when you aren’t a household name. It’s easy to be humble when you aren’t a multi-millionaire. At a certain level, they say, wealth and success change you.

Truth is, I’ve seen the full spectrum of wealth. Two of my grandparents cut hair for a living. Another was a security officer. Another a secretary. My dad was a middle school English teacher. My mom didn’t graduate college until I was in high school. I come from a long, proud history of middle-class Americans, both blue and white collar. After high school, I traveled all over the world with an international educational and cultural organization helping to build bridges of understanding between people and countries through the power of music and service. I stayed with generous host families who lived in shacks, and I lived with generous host families who lived in palaces. Later in life, when I founded two youth leadership programs, the National Leadership Academy, and the Global Youth Leadership Academy, I was supported by friends who have a net worth in the three figures and friends with a net worth in the nine figures.

All this to say, I have a rather good idea of how wealth affects people. Here’s what I’ve learned: Money does not change a person. It just reveals them. If you’re a jerk before you get successful, well, you’ll just be an even bigger jerk afterwards. If you were generous when you were poor, you’ll be even more generous when you’re rich. Wealth and success have the profound effect of amplifying the person you were before you had wealth and success.

The problem is that humility is not nearly valued enough. I read an article in Forbes recently explaining that the latest research shows “humble leaders are more likely to create healthier and more effective organizational cultures, to develop employees’ potential, as well as coach and mentor them, and boost team morale, job satisfaction, and performance.” Except, too often, confidence is mistaken for competence, arrogance is mistaken for strength, and—worst of all—humility is mistaken for weakness.

Let me tell you about my dear friend Jimmy Blanchard. When he was just twenty-eight, he became president of a small regional bank in the southern United States. Now, most 28-year-olds would get overconfident with a title like that. Not Jimmy. When the bank’s board of directors offered him the job, his reaction was: “Are you sure? I can’t even balance my own checking account. How can I be president of a bank?” 

How many 28-year-olds do you know who’d try to turn down the job of bank president? But the board knew the caliber of guy they had, because under Jimmy’s leadership, that tiny regional bank grew to have tens of billions of dollars in assets. Except, that’s not what Jimmy’s most proud of. His proudest legacy is helping to install a culture of love and servant leadership. By the time he retired, his bank had just one-fifth the employee turnover compared to the industry average, and it was ranked by Fortune Magazine as the No. 1 best place to work in America. That’s right: number one in the entire country.

 Today, Jimmy is a very wealthy man. But he is just as humble as the day he was tapped to become president of that little southern bank. He’s still the same guy who tried to turn the big job down. Jimmy is like my friend Bobby Creighton, who is one of the biggest stars on Broadway. (Robert Creighton is his stage name.) He grew up in a small town in Ontario, the youngest son of a local doctor. He worked hard and never gave up on his dreams, and he eventually starred in mega hits like “The Lion King,” “Frozen,” and “Chitty Chitty Bang Bang.” You’d think becoming theater royalty would change someone, but not Bobby. He’s still the humble boy from a small town in Ontario. After every show, my friend sticks around outside the theater to sign autographs for his fans, even when the rest of the cast slips out the back. He does it because he sees his own face in all those star-struck kids holding out their Playbills.

A few years ago, I traveled with my family to Maui for Christmas break. As I was recuperating by the pool from a bad boogie boarding accident, my son Tate ran off to find someone to have a catch with. Instead of a kid his age, he found two-time Major League Baseball MVP Christian Yelich, who spent two hours throwing the ball around with Tate and then took him to get a milkshake. During his own vacation. “Having a catch with your son made me remember why I love the game so much,” he told me. I later discovered that just days earlier, Christian and the Milwaukee Brewers had finalized a $215 million contract.

When I think about Jimmy, Bobby, and Christian, Tim McGraw’s song “Humble and Kind” comes to mind. It’s about never forgetting where you came from and staying true to your values, even when you find enormous success. As the song goes: When the work you put in is realized, let yourself feel the pride. But always stay humble and kind. 

You might not be the president of a bank, a famous Broadway star, or a major league baseball player, but maybe you’re on your way to something just as big. Maybe you’ve already arrived there. Maybe you’re in charge of five people, or maybe you’re in charge of 5,000. No matter where you are in life, remember that the greatest quality of being a heart-led leader is staying humble and kind. As Tim sings, When you get where you’re going, don’t forget turn back around and help the next one in line. Always stay humble and kind.