In 1926, James O. McKinsey developed a new type of service in Chicago, offering senior managers of large companies advice on improving their profitability. James O. McKinsey's innovative concept was to offer more than just limited expertise, such as legal advice; he provided competent consulting support to solve all of their business problems.

In 1933 he hired business lawyer Marvin Bower, who led McKinsey’s New York office from 1934. It was Marvin Bower who formulated the firm´s philosophy and principles still followed at McKinsey today. The core principles include professional independence to deliver the best possible results, the "client first, firm second, self third" principle, the "one-firm" partnership, and, finally, the "obligation to dissent." The firm grew rapidly and internationally over the years.

Now, more than 80 years later, the firm has grown into a global partnership serving more than 70 percent of Fortune magazine’s most admired list of companies and a diverse range of governmental institutions and non-profit organizations. About 80 percent of our projects come from clients with whom we have an established relationship.

McKinsey's global network covers industry and sector expertise and functional know-how in 83 offices in 45 countries. We speak over 120 languages and represent over 100 nationalities. Clients call on us to help them tackle their most important issues: how to seize opportunities brought on by globalization, how to rally their people around a new strategy, and how to make their operations more productive and enable profitable growth. Our breadth of expertise is as broad as the range of challenges facing senior management today.