Before the term "thought leader" got applied to anyone with a book contract and a  TEDx talk, Clayton Christensen was the real deal. Christensen, who died Thursday at age 67 after a long battle with cancer, fundamentally changed assumptions about the advantages to companies of incumbency and inspired corporate employees to indulge their entrepreneurial impulses outside the mother ship. He reframed our understanding of innovation toward making things more accessible--and in the process made innovation itself more accessible to a generation of founders. Are you building a disruptive business? Christensen's ideas are embedded in its foundation. 

In many ways, Christensen's seminal book, The Innovator's Dilemma (Harvard Business School Publishing, 1997), is about big-company defense. In it, he explained how corporations become vulnerable not because they can't identify and develop new ideas but because those ideas offer meager ROI from their existing customers, who want better versions of whatever the businesses offer now. For entrepreneurs, of course, that's an opportunity to play offense. With little to lose, they charge into these seemingly unappealing markets and make some change--typically the application of technology--that renders products and services cheaper, simpler, or more affordable. 

Christensen published Innovator's Dilemma in 1997, the year Amazon--the triumphant embodiment of his ideas--went public. Years later, Jeff  Bezos, who was now at the helm of a massive incumbent, applied lessons from Dilemma and the follow-up Innovator's Solution (Harvard Business School Publishing, 2003), co-authored with Michael E. Raynor, to disrupt himself: introducing the Kindle as a cheaper, more convenient alternative to the sale of physical books. Steve Jobs, Reed Hastings, and Andy Grove are among the many founders who incorporated Christensen's insights as they stormed or guarded the ramparts. 

Among Christensen's influential recent ideas is the "Jobs to Be Done" framework for understanding consumer behavior. In that model, people don't just buy things but rather bring products into their lives to make progress on something. When you hear a CEO ask her team "What is the job a customer is hiring this product to do?" you are hearing the influence of Christensen.

In later years, Christensen's work increasingly sought to improve lives, both individually and globally. His most recent book, The Prosperity Paradox: How Innovation Can Lift Nations Out of Poverty (Harper Business, 2019), co-authored by Efosa Ojomo and Karen Dillon, urged entrepreneurs to focus less on eliminating poverty in developing nations than on producing market-creating innovations that spawn jobs, profits (which can be reinvested in infrastructure and public services), and cultural change. 

Christensen's 2012 book, How Will You Measure Your Life? (Harper Business, 2012), co-authored by Dillon and James Allworth, is perhaps his most personal. Christensen--a soft-spoken but charismatic and commanding presence at 6'8"--was as gifted a teacher as he was a thinker. On the last day of his classes at Harvard Business School, he would ask his students to seek answers to three questions:

  • How can I be sure I'll be happy in my career?
  • How can I be sure my relationships with my spouse and other family members are an enduring source of happiness?
  • And how can I be sure I'll stay out of jail?

He wasn't kidding about that last one. Several accomplished people Christensen met during his career would go on to do time, including Enron's Jeffrey Skilling, who was an HBS classmate.

In How Will You Measure Your Life? Christensen argues that in life, as in business, how things turn out depends on where you allocate your resources: your time, your energy, and your passion. The father of five, grandfather of eight, and a deeply committed member of the Church of Jesus Christ of Latter-Day Saints, Christensen knew his core competency was more than writing business books. 

"If the decisions about where you invest your blood, sweat, and tears are not consistent with the person you aspire to be," wrote Christensen, "you'll never become that person."

Correction: An earlier version of this article misspelled Efosa Ojomo's first name.