Retired from the game, he and his brother opened a sporting goods store in Chicago, obtaining the rights to produce the official National League ball. The business, which grew rapidly over the next 25 years, with 14 stores by 1901, expanded from retail into manufacturing baseball equipment and is still a going concern. In 1900 Spalding was appointed by President McKinley as the USA's Commissioner at that year's Summer Olympic Games. Seven years later, his prompting would lead to the founding of the commission that (erroneously) declared baseball to be the invention of Abner Doubleday.
Receiving the archives of the late Henry Chadwick in 1908, Spalding combined these records with his own memories (and biases) to write "Americas National Game" (published 1911) which, despite its flaws, was probably the first scholarly account of the history of baseball.
He was elected to the Baseball Hall of Fame by the Veteran's Committee in 1939.
See: Spalding's page at the Hall Of Fame
Official webpage of Spalding's company
Spalding's career statistics at Baseball-Reference.com