The inventor of the first bank-issued credit card was John Biggins of the Flatbush National Bank of Brooklyn in New York. 

In 1946, Biggins invented the "Charge-It" program between bank customers and local merchants. The way it worked was that merchants could deposit sales slips into the bank and the bank billed the customer who used the card.

Credit cards were not always been made of plastic. Throughout history, there have been credit tokens made from metal coins, metal plates, and celluloid, metal, fiber, paper and now mostly plastic cards.