Pharmacist John Colgan, born in Louisville, in 1840, went through the public school system there, and to college in Somerset, OH. He returned to Louisville and opened a drug store at the corner of 1oth & Walnut Streets. While Colgan didn't INVENT chewing gum (in fact, some form has arguably been around since Greek civilization, if not longer), he had a strong hand in developing its popularity.
Legend has it he saw children peeling the bark off trees & chewing on it, so he ordered the main ingredient for chewing gum (again, this product already existed in the US), which is from a South American tree, and improved upon the existing product by sweetening it with powdered sugar. This resulted in a sticky substance he called "Colgan's Taffy Tolu Chewing Gum." Fortunately, the ingredients & manufacturing process remained "pure" enough that they were not affected by the 1906 Pure Food & Drug Act.
He sold his drugstore, went into business with James A. McAfee, & advertised all over - including a presentation by his son, William, of Colgan's Taffy Tolu at the 1893 Chicago World's Fair. Check out these other advertising campaigns:
His version of the gum became SO successful, it was sold internationally in Canada & Australia! Thomas Adams (a huge NY manufacturer & distributer of chewing gum at the time) even took inspiration from Colgan's development when he created Tutti-Frutti, the first gum sold in vending machines!
John Colgan died today (February 1) in 1916. He is buried in Cave Hill Cemetery, in Louisville. But his legacy lives on in the modern treat many of us still love to chew on today, first made sweet by Colgan's addition of powdered sugar!