Foster succeeded Henry Chadwick as editor of Spalding’s Guide in 1908. He had been the state editor of the Cleveland Press until 1888. When the sports editor of the Leader became ill, Foster replaced him. In 1896 he moved to New York, where he worked for the Evening Telegram and The Sun and for the Consolidated Press Association. He served as sports editor of the Telegram for 15 years. He was secretary of the New York Giants from 1913 to 1919, then returned to The Sun until 1931. A member of the original rules committee, he was an authority on baseball rules, law, and administration. He was said to have answered more than 500,000 questions by mail on all phases of the game.