Since the 1940s, Drucker did consulting work for nearly every major corporation, including General Electric, Coca-Cola, Citicorp, IBM and Intel, but also for numerous governmental and non-governmental organizations both home and abroad. And he made the personal acquaintance of, as well as advised, nearly every key figure of the American economy in the second half of the 20th century: starting with Alfred Sloan, the legendary first general director of General Motors, and his colleague Charles E. Wilson, who with GM developed the model of retirement funds, to contemporary captains of industry like Jack Welch of General Electric and Andrew Grove of Intel. Both expressed the highest praise for Drucker in a 1997 cover story of the American economic magazine Forbes. Grove was quoted as saying: "Drucker is a hero of mine. He writes and thinks with such exquisite clarity - a standout among a bunch of muddled fad mongers."
Peter Drucker's consultations had an almost legendary reputation in business circles. With his detailed knowledge of history, Drucker was able to illuminate questions of company structures and business strategies in broad economic-historical contexts. As in his lectures and books, Drucker did not limit himself to purely scientific contexts, but would on occasion also quote literary figures like Henry James or Jane Austen, both of whom he especially valued. Or he illustrated his considerations with current events or anecdotes from Old Vienna.
But to Drucker management was "no specific peculiarity of business enterprises, but rather the specific organ of all institutions of modern society." One of his personal concerns was the sponsorship of non-profit organizations, especially in the social sector. For a long time, he did consulting free of charge for social welfare and charitable organizations, among them CARE, the Salvation Army and the American Red Cross, which he considered to make essential contributions to the functioning of a civil society of solidarity.
Especially in his later years, Drucker became concerned about the development of an aggressive capitalism which disregards social aspects: "Free enterprise cannot be justified as being good for business. It can be justified only as being good for society."