Polish immigrant Jacob Sapirstein began purchasing cards from German manufacturers and selling them in the Cleveland area shortly after arriving in America in 1905. It became a family operation called the Sapirstein Greeting Card Company.
The company started printing its own cards by 1936 and changed its name to American Greetings Publishers during World War II. The company continues to operate today.
Source: American Greetings – Through the Decades: Milestones and Moments