Having grown up around the Union Pacific, Robert Lovett had railroads in his blood, yet it was in the air that he would first distinguish himself.

In spring 1916, during his sophomore year at Yale, Lovett joined what would become the First Yale Unit of the Naval Reserve Flying Corps. He quickly emerged as the group’s most capable pilot, and when the United States entered World War I, he was assigned to the Royal Naval Air Service.

After the war, Lovett married Adele Brown, daughter of Brown Brothers’ senior member James Brown. His father-in-law convinced him to try Harvard Business School, but more schooling held no interest for him, and he fled to Wall Street a few months later, joining Brown Brothers in 1921. He would spend at least three months a year in Europe throughout the 1920s and 1930s, including a stint with Brown Shipley in London.

If his eye for detail made him a superb manager, he was also a strategic thinker of the first order. In a 1925 study, Lovett anticipated by more than a half century one of the governing principles of today’s firm—that it should engage only in specialized businesses where it had a competitive advantage—even if this led him to the radical conclusion that the firm should split into a corporation focused on banking and partnership dealing in securities.

Lovett had the personal qualities that made him a good partner, including a sense of tact, a respect for civility, and a congenial wit. He excelled at resolving conflict and forging consensus. He chose his words carefully, which gave them more force. “He didn’t enter into conversation unless he had something to contribute,” Averell Harriman noted.

Despite a busy career at Brown Brothers Harriman, Lovett never lost his interest in aviation.

After serving as U.S. assistant secretary of war for air during the Second World War, he was appointed as U.S. undersecretary of state, helping to shepherd the Marshall Plan through Congress. And as deputy secretary of defense from 1950 to 1951 and finally as secretary of defense from 1951 to 1953, he made air power the center of U.S. military strategy.

Lovett was convinced that 12 years in Washington, including several as head of the largest military in the world, had made him a better executive. “The most important thing that a business executive can have is skepticism. When you ask, ‘How is the 44th Division doing?’ and the reply is ‘Everything is fine, Mr. Secretary,’ well, you probe around and find...that you’ve got a lot of dead wood on your hands. Dead wood left alone too long becomes combustible. The next thing you know you’ve got a forest fire on your hands.”