William McCormick Blair Jr., a former United States ambassador to Denmark and the Philippines and a confidant of Adlai E. Stevenson. Mr. Blair was born in Chicago on Oct. 24, 1916. His father was a financier and president of the Art Institute of Chicago. His mother was the former Helen Haddock Bowen. Mr. Blair was a descendant of Cyrus Hall McCormick, the inventor of the mechanical reaper, and a grandson of Louise deKoven Bowen, a philanthropist and social reformer who helped Jane Addams begin the Hull House settlement in Chicago. Mr. Blair graduated from Stanford; served in the Army Air Forces’ intelligence operations in China, Myanmar (then called Burma) and India, rising to the rank of captain; and returned to earn a degree at the University of Virginia School of Law. He was director of the Chicago Council on Foreign Relations, since renamed the Chicago Council on Global Affairs, and was appointed administrative assistant to the governor in 1950, during Mr. Stevenson’s first term. As ambassador to Denmark during the Kennedy administration, he married the former Catherine Gerlach, known as Deeda, in the chapel of Frederiksborg Castle. She became a public health advocate. (Their son, William III, predeceased him.) Mr. Blair was envoy to the Philippines from 1964 to 1967 and, later, president of the Council of American Ambassadors. He and Mr. Stevenson were law partners with W. Willard Wirtz, named under secretary of labor and then labor secretary by the Kennedy administration, and Newton N. Minow, who became the chairman of the Federal Communications Commission in 1961.