American pharmacist and businessman, known as the father of the modern drugstore. He created the largest retail drugstore chain in the United States.

Walgreen was the son of Swedish immigrants and moved with his parents to Dixon, Ill., in 1887. After attending business college, he worked in a shoe factory there but soon became interested in pharmacology. He moved to Chicago in 1893 and became a registered pharmacist in 1897. He enlisted and served during the Spanish-American War, and upon his return to the United States, he again worked in Chicago as a pharmacist. He bought his first store in 1902 and established C.R. Walgreen & Company in 1909. In 1916 the name was changed to Walgreen Company. By the time of Walgreen's death, more than 490 stores were operated by the company.

Among Walgreen's many innovations was open-display merchandising. He is also noted for popularizing the lunch counter. He was president of the company until August 1939. He donated an airport to the town of Dixon and established (1937) a foundation for the study of American institutions at the University of Chicago.