After college, he served in the U.S. Army in World War II and later worked for the Department of Agriculture as an economist.

[8][9] He was initially denied entry to the doctoral studies at the London School of Economics and was instead admitted to the Master's program.

After impressing onlookers with his debating skills at Lionel Robbins' seminars, he was within weeks switched to the doctoral program and also admitted to the faculty as an Assistant Lecturer.

[10] While a professor at Princeton University he supervised some graduate students who would eventually become very well-known economists, including Burton Malkiel, William G. Bowen, and Harold Tafler Shapiro.

[1] Among his better-known contributions are the theory of contestable markets, the Baumol-Tobin model of transactions demand for money, Baumol's cost disease, which discusses the rising costs associated with service industries, Baumol's sales revenue maximization model[11] and Pigou taxes.

"[21] The British news magazine, The Economist published an article about William Baumol and his lifelong work to develop a place in economic theory for the entrepreneur (March 11, 2006, pp 68), much of which owes its genesis to Joseph Schumpeter.

They note that traditional microeconomic theory normally holds a place for 'prices' and 'firms' but not for that (seemingly) important engine of innovation, the entrepreneur.

An entire generation of economics students was familiar with this book ....[24]Baumol was a trustee of Economists for Peace and Security.

Microeconomics of market failures (English translation of the (1998) French Microéconomie: Les défaillances du marché (Economica, Paris) ed.).