My hometown of Louisville, KY was the center of the universe last week as we bid farewell and celebrated the life of Muhammad Ali. There are only a few “larger than life” people that each of us will experience during our lives, and he was certainly one of them. He virtually invented trash talking, was one of the first poet rappers, and was the first major athlete/celebrity to adopt a Muslim name (Lew Alcindor became Kareem four years after Ali).

Ali was both criticized and celebrated for his stance on the draft. As time passed and it became clear that he was truly committed to his religion and sincere in his beliefs, views on him softened, and he became an almost universally beloved figure. But there is another reason for that happened which has lessons for us in the business world – vulnerability.

Standing over Sonny Liston in the iconic photo from their 1965 rematch, Muhammad Ali did not appear very vulnerable. His words and brash talk for the next 16 years did not indicate much vulnerability either.  However, after he was diagnosed with Parkinson’s in 1984, all of that changed. He not only faced his disease with courage, but with total openness and vulnerability. Even in his final months, he did not shy away from public appearances. And who among us wasn’t moved by his courageous lighting of the Olympic torch in 1996?

Vulnerability is a key element in earning trust as a leader, which is foundational to building healthy teams. Patrick Lencioni defines vulnerability-based trust as a place where leaders “comfortably and quickly acknowledge, without provocation, their mistakes, weaknesses, failures, and needs for help. They also recognize the strengths of others, even when those strengths exceed their own.” Noted writer and speaker Brené Brown (her TED Talk “The Power of Vulnerability” has been viewed over 25 million times) describes vulnerability as “the courage to be imperfect” or to “dare greatly”. As Brown points out as a counter-example, vulnerability is not something we see much in politics today.

Leaders who think they need to be perfect, always right and always have the answer, will never be accepted as authentic, will never connect with people, and will never inspire others. In the last 32 years of his life, Muhammad Ali became almost universally admired (dare I say loved?), connected with people across the globe, and inspired others in large part through his vulnerability – his courage to be imperfect. This lesson may be one of “The Greatest” legacies he leaves us with.