The cause was complications from leukemia, said Harvard Business School spokesman Brian Kenny.

A former all-state basketball player and local leader of the Church of Jesus Christ of Latter-day Saints, Dr. Christensen was perhaps an unlikely Ivy League academic. Raised in poverty on the west side of Salt Lake City, he demonstrated a somewhat extreme brand of thriftiness, saving tray liners from fast-food restaurants and driving the same Chevy Nova for years, even though his 6-foot-8 frame left him pressed against the ceiling.

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He had previously worked as a consultant at Boston Consulting Group and co-founded an advanced materials company before joining the Harvard faculty in 1992, deciding he was better suited as an analyst than as an executive. “When people would ask him hard questions,” his colleague Derek van Bever recalled by phone, “he’d always say, ‘Well, what you want to do is quit your job and become a professor at Harvard Business School, because then all you have to do is ask the questions, not answer them.’ ”

It was a self-effacing response from a man who spent most of his career answering a deceptively straightforward question: Why do companies fail? Or rather: How is it that a small start-up can take on an industry giant — one with a robust research lab and seemingly top-notch management — and win? Paradoxically, Dr. Christensen found that many companies succeeded not by making something better, but by building something worse, manufacturing shoddy and inexpensive products that catered to the low end of the market.

One of his favorite examples involved the construction of rebar, pieces of relatively cheap steel used to reinforce concrete. Within the steel industry, rebar proved a boon to minimills, in which scrap is melted in small electric furnaces rather than in the enormous integrated mills used by major companies.

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The minimills took over the rebar market, initially to the delight of integrated mill businesses that sought to focus on higher-margin products such as automobiles.

But soon enough, Dr. Christensen said, the minimills expanded their reach, improving their manufacturing methods and pushing the old giants out of business. Something similar happened when, in the 1950s, Sony released cheap transistor radios, which primarily appealed to teenagers before reaching a wider audience and overtaking fancier radios by RCA and Zenith. Dr. Christensen found that the same model played out with everything from excavators to affordable Model T automobiles — “disruptive technologies,” as he put it, at the center of a process he came to call “disruptive innovation.”

With colleague Joseph L. Bower, Dr. Christensen outlined his theory in a 1995 article for the Harvard Business Review. He later distilled his findings into a book, “The Innovator’s Dilemma” (1997), which became a runaway hit after Intel chief executive Andy Grove called it the most important book he’d read in a decade. Dr. Christensen and Grove appeared on a 1999 cover of Forbes together, and the Economist magazine later named “The Innovator’s Dilemma” one of the six greatest business books ever written.

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Its acolytes included billionaire businessman Mike Bloomberg, Apple co-founder Steve Jobs and Netflix chief executive Reed Hastings. When Dr. Christensen published a follow-up, “The Innovator’s Solution” (2003), Amazon founder and Washington Post owner Jeff Bezos shared it with his top executives. Among Silicon Valley start-ups and investors, “disruption” became an inescapable buzzword, for better or for worse.

“Everybody talks about disruption now,” investor and tech writer George Gilder told the New Yorker in 2012. “Clayton inserted that word in the mind of every CEO in technology. Everywhere you go, people explain that they’re disrupting this or disrupting that.”

Dr. Christensen urged companies to establish research-and-development labs beyond the reach of their corporate headquarters to develop low-end products that might minimize the risk of death by disruption. He also expanded his theory to encompass “new-market disruption”; co-wrote books that applied his theory to health care, public school and higher education; and lamented the use of “disruption” to describe companies such as Uber, which failed to meet his low-end or new-market uses of the term.

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He also faced some criticism from scholars, notably in a 2014 New Yorker article by Harvard historian Jill Lepore, who wrote that his “sources are often dubious and his logic questionable.” But he remained a superstar in academia and on the corporate lecture circuit, reportedly earning $100,000 per talk and continually working to refine his theories, even after a stroke in 2010 forced him to spend more than a year working to recover his vocabulary.

“The key to his power as a thinker and a theoretician is that most of us look for evidence that confirms our beliefs, and Clay did just the opposite,” said van Bever, who directs the Forum for Growth & Innovation, a Harvard Business School project inspired by Dr. Christensen’s research. “He welcomed evidence that disconfirmed things that he believed.” To that end, he hung a distinctive sign outside his office door: “Anomalies Wanted.”

The second of eight children, Clayton Magleby Christensen was born in Salt Lake City on April 6, 1952. His father worked in the grocery division of a department store, and his mother taught high school and wrote for radio and television.

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Both were active in the Mormon Church, and Dr. Christensen said he inherited their focus on faith and family, serving a two-year mission in South Korea and later devoting each Saturday to his children and every Sunday to God. He also came home early on weeknights for family dinners. “Sometimes, in order to keep these commitments, he would go to work at three in the morning,” the New Yorker reported.

He received a bachelor’s degree in economics from Brigham Young University in 1975 and studied at Oxford University as a Rhodes scholar, receiving a master’s in applied econometrics in 1977. Two years later, he graduated from Harvard Business School.

Dr. Christensen returned to Harvard to receive a doctorate in business administration in 1992. He was named a full professor there six years later, after the success of “The Innovator’s Dilemma” — a book that drew the attention of William S. Cohen, then the secretary of defense, who reportedly invited him to deliver an innovation talk attended by the Joint Chiefs as well as the secretaries of the Army, Navy and Air Force.

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In 1976, he married Christine Quinn. In addition to his wife, survivors include five children; five siblings; and nine grandchildren.

Dr. Christensen’s health struggles a decade ago included a heart attack and cancer diagnosis, in addition to the stroke — events that led him to reassess his own legacy in a book, “How Will You Measure Your Life?” (2012), which applied business concepts to personal ethics.

“While many of us might default to measuring our lives by summary statistics, such as number of people presided over, number of awards, or dollars accumulated in a bank, and so on, the only metrics that will truly matter to my life are the individuals whom I have been able to help, one by one, to become better people,” he wrote. “When I have my interview with God, our conversation will focus on the individuals whose self-esteem I was able to strengthen, whose faith I was able to reinforce, and whose discomfort I was able to assuage — a doer of good, regardless of what assignment I had. These are the metrics that matter in measuring my life.”