In my forties, I was unhappy with my career and where it was heading.

Driving home on a beautiful fall afternoon, I looked in the rearview mirror and saw a miserable person—me. On the surface, I appeared to be confident and successful, but inside I was deeply unhappy.

For 20 years, I had been a successful executive on a fast track to the top, or so I hoped. I was getting closer to that goal, as I took on responsibility for Honeywell’s most challenging businesses. At the time, I was on my third set of turnarounds, responsible for three groups, nine divisions, and 18,000 employees. Yet I began to wonder if Honeywell was the right place for me.

As executive vice president of Space and Aviation Systems, my team and I uncovered losses exceeding $500 million that had not been recognized or accounted for properly. Presenting this news to Honeywell’s board caused a great deal of concern. As I said to myself repeatedly, “I didn’t create this mess. I’m just the guy who has to fix it.” I always saw myself as a builder, not a turnaround expert, but I did what needed to be done to restore Honeywell’s businesses to long-term health.

But on that autumn day, I realized I wasn’t passionate about Honeywell’s businesses. Even worse, I was becoming more concerned about becoming CEO than being a leader who could make a positive impact on the world. I faced the reality that Honeywell was changing me more than I was changing it—and I didn’t like the changes I saw in myself.

David Brooks’ The Road to Character challenges us to consider our resume virtues against our eulogy virtues. Resume virtues are what we write about ourselves to measure up to the world’s expectations. Eulogy virtues are what others say about us at our funeral: what kind of person we were and how we cared for others.

Many of us focus on resume virtues because they’re easy to measure and give us superficial self-esteem. Earning a lot of money, receiving promotions and prestigious titles, and having power over others are easy ways to gauge success. But more difficult tasks—like making a positive difference in the lives of others or becoming the type of person you want to be—have few measurable benchmarks.

When I was at Honeywell (HON), I had all the trappings of success, but my life lacked the significance I yearned for. That day I recognized I needed to get back to what I call my True North. Your True North, which is derived from your beliefs, values, and the principles you use to lead others, is your internal compass. It’s unique to you and it represents who you are at your deepest level.

With my wife Penny’s encouragement and support from my men’s group, I reopened job discussions with medical device company Medtronic (MDT), which was at the time a much smaller company but one with a passion to help millions of people live a full, healthy life. After having interviews with the CEO, the founder, and board members, I accepted Medtronic’s offer and became president and chief operating officer at the company. Two years later, I was elected CEO.

At Medtronic, I found a place—or it found me—that let me focus on significance over success. Medtronic’s mission inspired me from the moment its founder Earl Bakken described it to me. When I arrived in 1989, Medtronic helped restore someone to health once every 100 seconds. By the time I completed my tenure in 2002, that figure had fallen to five seconds. Today it is down to one second, with 30 million new patients every year. That’s a much more meaningful metric than a stock price.

What’s significant in your life may change over time. After retiring from Medtronic in my late 50s, my purpose changed from leading large organizations to helping other people lead authentically by discovering their True North. Teaching authentic leadership at Harvard Business School the past 15 years, I receive a modest salary and have no positional power, yet I find great significance in the work I am doing. As one friend told me, “Bill, you seem to take vicarious pleasure in the accomplishments of others.” Indeed, I do.

While helping people lead authentically is my mission, it doesn’t impede other areas of deep importance to me. My family, friends, colleagues, and mentees provide consistent sources of significance. In 1975, I began a men’s group with four close friends after a weekend retreat, and four others soon joined us. Forty years later, we’re still meeting weekly to discuss our spiritual beliefs, our aspirations, career challenges, marriage and family problems, and the process of personal development.

How will you measure your life? That’s the title of my HBS colleague Clay Christensen’s latest book. Are you striving so hard to find success that you’re playing the world’s game rather than fulfilling your core desires? If so, I encourage you to pull back and reflect on your life. Go on a spiritual retreat or start a journal. Better yet, engage a mentor, therapist, or close friend to dig deep into what’s most important to you.

This is hard work, as you peel back the layers of your inner self and learn to accept yourself fully, weaknesses and all. It means digging deeply into past wounds, failures, and disappointments, and discovering what you learned about yourself that can guide you going forward. To get started, think about the end of your life and hypothesize your granddaughter asking you, “What did you do to make a difference in the world?” What will you tell her?

The time to start acting on that is now, not then. Life beckons you. Don’t wait until it’s too late. You may discover that what’s missing in your life is not success, but significance. We only go around once in life, so we need to seek all the wonders it has to offer.

Bill George is Senior Fellow at Harvard Business School, former Chairman & CEO of Medtronic, and author of Discover Your True North.