The National Archives published an article about the history of this position. It claims that the first was George B. (M.) Cortelyou, who held a number of Cabinet posts, when he invited the press into the White House to discuss President William McKinley's condition after the then attempted assassination attempt at the Pan American Exposition in Buffalo, NY. Some of the surviving photos show him standing with the President there. He began as a shorthand teacher in NYC, later Chairman of the Republican Party and then under President Theodore Roosevelt, Postmaster General, and one of the early CEOs of Consolidated Edison in NYC (in their museum on 14th and 3rd Ave). He later lived in Huntington, NY at "Harbor Lights" recently for sale for over 3 million. Historians have suggested his role as overlooked in the history of the US during the Spanish-American War and the McKinley-Roosevelt administration, and his role should be examined by historians, even if they are all in shorthand, perhaps. He was descended from the French Surveyor for the Dutch in New Amsterdam (NYC) of what narrowly became a borough, Brooklyn, NY (by a few votes, once a very large city almost to itself). Oddly the article left out the first woman in that role Dee Dee Myers, though she had already vacated it to get married a year or two before the article. (Nice editing tools Slate!)