Bill Sahlman’s office at Harvard Business School once held sixty five boxes of paper, books, notes, drafts, and artifacts from a lifetime spent thinking seriously about how new things come into the world. On the last day of 2025, those boxes were sealed and wheeled away by a moving company. The shelves emptied. The room went quiet. Bill turned seventy five the next morning. It was a clean ending, and a generous one, to a career that reshaped how entrepreneurship is taught, practiced, and understood.
Few professors, if ever, have had more of an impact. For me, that impact has been personal. Bill was my teacher, then my mentor, and over time, a dear friend. The lessons stayed long after the classroom, shaping how I think about risk, trust, and what it means to build something that lasts.
Bill never fit neatly into a single category. He is often described as a professor of entrepreneurship or finance, but that framing misses something essential. His real subject was judgment. How people make decisions when information is incomplete, incentives are misaligned, and the future refuses to cooperate. He was less interested in answers than in how one arrives at them, and in how easily smart people can fool themselves along the way.
Across more than five decades as a student, research assistant, and faculty member, Bill taught over six thousand students. Many of them remain close friends. Some now teach the very courses he helped invent. Others went on to build companies, funds, schools, and institutions. Quite a few are now old enough for Medicare, a fact Bill notes with dry humor and a certain disbelief that time really does move that fast.
In 1985, he developed a course called Entrepreneurial Finance. At the time, the idea that entrepreneurship deserved its own analytical framework was still new. The course became foundational. Bill taught it thirty times, and versions of it spread to business schools around the world. What distinguished it was not an obsession with valuation spreadsheets or deal mechanics, but a steady focus on tradeoffs, timing, and trust. Capital mattered. People mattered more. Context mattered. And everything changed over time.
In 2001, Bill helped launch The Entrepreneurial Manager, a required first year course that reframed entrepreneurship as a method of managing rather than a personality trait. Years later, students in that same course would study a case he co authored on Sal Khan’s decision to launch Khanmigo, an AI based personal tutor aimed at reaching every student in the world. The technologies evolved. The questions did not.
Bill pushed his ideas far beyond Aldrich Hall. In 2017, he developed an online course called Entrepreneurship Essentials. In 2020, he created Entrepreneurial Solutions to World Problems, an explicit statement of his belief that entrepreneurship, at its best, is a civic act. Over the course of his career, he developed more than 250 articles, cases, exercises, and technical notes, and co authored one textbook. Harvard Business School Publishing sold more than three million copies of this work, a quiet measure of how widely his thinking traveled.
He also built institutions. He helped launch the HBS California Research Center, the HBS New Venture Competition, and the President’s Challenge at the I Lab. He served as chair of the Harvard University Advisory Committee on Shareholder Responsibility, as Senior Associate Dean of HBS Publishing, as Senior Associate Dean for External Relations, and as co chair of both the Entrepreneurial Management Unit and the Rock Center for Entrepreneurship. He worked globally with Endeavor and helped found the advisory board for Harvard Stem Science.
Running alongside the academic life was another one, equally instructive. Bill advised, invested in, or served on the boards of several hundred ventures and venture capital funds. More than one hundred of those ventures failed. He talks about this without embarrassment. You can only lose one hundred percent of your investment, he likes to say. The upside has no limit. Failure was not a theoretical construct for him. It was data.
Building on Howard Stevenson’s insight that entrepreneurship is the pursuit of opportunity beyond resources currently controlled, Bill developed a framework centered on four elements and their fit over time: people, opportunity, context, and deal. He encouraged structured experimentation. Form a testable hypothesis. Assemble just enough human, financial, and intellectual capital. Run an experiment. Learn. Decide what to do next. In this model, entrepreneurs are in the information production business. Investors are in the information acquisition business.
He distilled entrepreneurial finance into four simple rules. More cash beats less. Cash sooner beats cash later. Less risky cash beats riskier cash. And do not run out of cash. Then he added the line that mattered most. Ventures do not run out of cash. They run out of trust.
As he steps into retirement, Bill remains engaged. He is drawn to sense making and critical thinking. He is unsettled by the pervasive negativism of modern media and politics. He believes deeply that entrepreneurs view problems as opportunities, and that their work, done well, can make the world better rather than merely richer.
Throughout all of this, Carol has been on the journey since their marriage in June of 1973. Bill is the first to say that none of this would have been possible without her support, wisdom, and honest feedback.
