[Editor’s note: This is part 8 of a 10-part series examining the building blocks of effective L.E.A.D.E.R.S.H.I.P.]

"Humility does not mean thinking less of yourself.... [It is] freedom from thinking of yourself at all." ---William Temple

At this point in our Leadership series, I hope you've begun to think of these essential building blocks as an interlocking structure that strengthens your ability to lead. As we saw last week, for example, reliability is one of the linchpins in the exercise and the embodiment of many of these qualities.

There's another even rarer seed that is not so easy to come by. You may not see it very often in the business leaders with whom you're familiar. But as bread won't rise without yeast, a business without a humble leader can have difficulties. So in our acronym for the building blocks of leadership, this week we explore H = humility.

In truth, I suspect that one of the reasons I chose humility is because it is such a rare but admirable quality. In my lifetime, no one more earnestly embodied this enviable trait than my father. As like the quote from William Temple, he judged no one (maybe his sons when they were acting up in church), and it never occurred to him that he was better than anyone else. He only saw that he had different gifts to share but would respond not a whit differently if you stepped out of a limousine or crawled from under a cardboard shelter. (In my case, I wish the apple had fallen a little closer to the tree.)

Having a modest opinion of your importance or standing may sound like weakness to some people. Yet, humility is a dominant thread of great leaders because it is a powerful magnet to get high performers to follow you over the hill.

In a welcome stroke of serendipity, I was preparing for some upcoming meetings when I was reminded of Jim Collins' description of a "Level 5 Leader" as a "triumph of humility and fierce resolve." It's a characteristic of every single leader whose company moved from "good to great," as described in Mr. Collins' book by the same name. (Mr. Collins also emphasizes the power of D = Discipline, another of our essential leadership building blocks.)

Humility makes it safe for you to admit your mistakes. People don’t expect you to be perfect. Quite the contrary, your willingness to admit your mistakes reflects your humanness, your vulnerability and your similarity to everyone else who makes mistakes every day. Our peers and comrades will usually give us an extra coil of rope when we humbly acknowledge our own errors, work to fix them and do it in a nonjudgmental manner that looks in the mirror for responsibility not out the window. Even the greatest leaders are imperfect, and usually the people working for them recognize that. None of us fails to fail.

Humility also means that we're willing to acknowledge that we don't know everything. We welcome talents from all corners of the realm and welcome those whose talents exceed our own. We don't sit in judgment of other people. We recognize that everyone has the potential to be a valuable contributor, and while they may not meet the standard required for a specific role, it doesn't mean there is no suitable role. We don't "judge a book by its cover" because we're willing to take the time to understand what’s between the covers and won't be consumed by the colors or powerful imagery that appear on the cover.

In our Leadership series, we've talked about service. Humility and it are closely intertwined threads in the tapestry of L.E.A.D.E.R.S.H.I.P. To become a servant-leader requires humility, and it is enhanced by our willingness to serve others.

Humility is really the open door to a penalty-free environment where experiments and action are supreme, and failure is simply a stepping stone to greater success. In a penalty-free environment, admitting mistakes and moving on is a welcome approach. Blame and judgment are set aside.

It's much like the process I described in any earlier column "Powerful After Action Reviews." The only objective is to improve future results, not finger-point about what’s already happened. Without humility, there’s only a closed door to this universe, behind which are hidden the demons of disappointment and failure.

No one has figured out whether the "humility gene" is born or made. Mr. Collins concluded that there are “those that have the Level 5 seed and those who don’t." But, that doesn't mean you can't become more humble or less judgmental, more supportive or less blameful, all of which will help pry open the doors of superior leadership and performance.

Be humble. Serve others. Excel. It is a rare but potent combination.

Lary Kirchenbauer is the president of Exkalibur Advisors, providing practical business strategies for middle-market businesses. Exkalibur works closely with senior executives and their businesses at the intersection of leadership, finance and business strategy. He recently hosted a Cash Flow Workshop, “It’s Midnight. Do you Know Where Your Cash Is?" Subscribe to his newsletter at www.Exkalibur.com. You’ll also find a library of valuable resources, including a new video and podcast library as well as articles and insights related to middle-market businesses.