Jack Shewmaker, the personification of ambiguity, a man of stunning contradiction and uncommon perplexity, was never as successful as he wanted to be — or as successful as he thought he should be.

Jack Shewmaker, the personification of ambiguity, a man of stunning contradiction and uncommon perplexity, was never as successful as he wanted to be — or as successful as he thought he should be.

He was by turn president and vice chairman of Walmart, the most successful retailer of all time, as that company hurtled inexorably toward the pinnacle of global retailing. In his executive capacity, he was largely responsible for Walmart’s leap into technology and for its EDLP (Everyday Low Price) strategy, one generally regarded as integral to the retailer’s astonishing success.

Yet when Walmart finally surpassed Sears and Kmart to become the world’s largest retailer, and when the retailer made its most dramatic global penetration, Shewmaker had departed, leaving David Glass, who had become Walmart’s chief executive officer, to receive most of the accolades.

He was undeniably one of the truly legendary retailing executives of his generation. When he joined Walmart in 1970, the retailer operated just 15 stores. When he departed 18 years later, he left a company that had transformed both retailing and business in America. Yet despite his pivotal role in that transformation, he never quite got the credit he so richly deserved — simply because the executive he left behind was the legendary Sam Walton.

He was a compelling speaker, combining understated middle-American humor and remarkable insight into both retailing and the human condition with a unique talent for engaging and involving his audience. He unfailingly delivered a message that spoke to the essential value of the individual within the context of a wider organization — and a wider world. Though he could sometimes speak for over an hour, his audience never lost interest — and Shewmaker never lost an audience. More important, the people who listened to what he had to say were invariably richer for the experience.

Yet, once he left Walmart and the halo that that retailer conferred, organizations and audiences lost interest in him , convinced, erroneously, as they were that Shewmaker’s time in the retail firmament had passed.

His career after Walmart was richer, more productive and more fulfilling than the entire business lives of most executives. As a consultant, he was instrumental in transforming Woolworth’s, an ordinary Australian grocery chain, into that country’s premier retailer — and one of the most admired retail companies in the world. He was the guiding force behind Students in Free Enterprise (SIFE), the college campus-based organization that has successfully taught generations of college students the workings and value of capitalism, while in the bargain providing an immense and immensely valuable talent pool for some of America’s most successful corporations.

Yet Walmart’s legendary global achievements had the curious but understandable effect of minimizing Shewmaker’s own global reach and considerable accomplishments that took him to every corner of the globe.

He served on Walmart’s board for 20 years after leaving the company, always closely involved, invariably challenging his fellow board members, often adopting positions that, while controversial, were both correct and ­perspicacious.

Yet when the mandatory retirement age as a Walmart board member arrived, he was unaccountably allowed to depart, despite his professed willingness to remain as a consultant to the company.

No more compelling, multifaceted or larger-than-life figure ever graced the retail stage. His presence and contributions repeatedly touched and altered the worlds of business, academia and health care in ways not equaled before or since. As a member of the board of directors at Cleveland Clinic, one of America’s prominent medical institutions, his contributions, grounded on his intellect, intelligence, curiosity, determination to make a difference, and unique ability to prepare for every meeting, dwarfed those of virtually every other board member. Yet his tenure on the Cleveland Clinic board suddenly ended.

He gave millions to a variety of institutions and offered his insight and expertise to a variety of organizations, each of which became stronger because of Shewmaker’s involvement. Yet these involvements never quite replaced, at least in his own mind, those heady, halcyon days of the 1970s and ’80s when Walmart was the only story — and Shewmaker one of just two people in a position to tell it.

Shewmaker was an adventurer of a kind America no longer produces. He skied in Alaska, fished in South America’s biggest and most dangerous rivers, explored the world’s uncharted terrain, roamed the earth with his wife, Melba, in search of new people, new experiences and new horizons. Yet, typical of Shewmaker’s view of himself and his sense of adventure, one of the stories he most enjoyed telling was of the time that he and Melba almost capsized in a typhoon off the coast of Antarctica.

He built one of the largest cattle ranches in the country, one renowned for breeding and showing registered Black Angus. He could boast one of America’s legendary classic car collections. He was accomplished on a motorcycle. Yet one of the recollections that come most sharply to mind when Shewmaker’s friends gather to reminisce about him was his near-death experience on a motorcycle when he was forced off the road and down an embankment near his home in Bentonville on his way to meet his son for lunch. Only the clear thinking and unerring instincts of Melba Shewmaker, who correctly reasoned that something was amiss when he failed to meet his son, saved his life. No, Jack Shewmaker was never the success he wanted to be. What he wanted most of all was to run Walmart — an opportunity that eluded him forever when he left the company 23 years ago.

But for those who knew him, Jack Shewmaker personified success. He was a giant by every definition of the word — in his physical stature, in the way he thought, in the way he carried himself, in the way he approached an assignment, in the way he mastered a challenge. Most people would have died in that ditch in northwest Arkansas. Shewmaker, his body broken and almost wrecked beyond repair, willed himself to live.

What those who knew Shewmaker best remember is that he always had time for people, especially for people in need of help or guidance, and most especially, for people he liked.

When Roger Corbett, chief executive officer of the Woolworth’s chain for which he consulted, told Shewmaker that one of his daughters was about to be married, he and Melba flew to Australia for the wedding. (Not surprisingly, Corbett and his wife, Rosemary, flew to Bentonville for Shewmaker’s funeral.)

Jack Shewmaker was terribly, heartbreakingly human. His fragile ego could be instantly deflated, his feelings easily hurt. He was sometimes quick to anger, slow to forgive. Yet those were, in the end, the very qualities that made him irresistible. To have Jack Shewmaker as a friend was all anyone could wish for. To have him as an advisor, consultant or confidant was more than one could reasonably expect or hope for.

Yet for countless people across America and in all corners of the world, Shewmaker was all of those things — and then some.

Now he’s gone, having suddenly passed away at the age of 72, the victim of a massive heart attack. For the countless thousands of people whom he touched, and the hundreds who are the better for having known him, the loss is already beyond calculating. In the coming weeks and months it will become unbearable.