In York, Pennsylvania, Henry C. Kessler first concocted this confection in the late 1930s at his candy factory, the York Cone Company. The company was originally established to make ice cream cones, but by the end of World War II, the peppermint patty had become so popular that the company discontinued all other products. In 1972, the company was sold to Peter Paul, manufacturers of Almond Joy and Mounds. Cadbury USA purchased the firm in 1978, and in 1988 the York Peppermint Pattie became the property of Hershey USA.

Many chocolate-covered peppermints had been made before the York Peppermint Pattie came on the market, but Kesslers version was firm and crisp, while the competition was soft and gummy. One former employee and York resident remembered the final test the patty went through before it left the factory. "It was a snap test. If the candy didn't break clean in the middle, it was a second." For years, seconds were sold to visitors at the plant for fifty cents a pound.